“ One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.”
This has been my experience. And I’ve had oncologists echo exactly this. In the words of one: MRIs find too much.
The CT and the PET/CT are the gold standards for finding cancer, finding recurrences, and staging cancer. The trouble is the radiation dose.
MRI provides very inconclusive results. You’ll see something but it’ll be unclear what it is. And often what you see is not even visible on a CT. Or it’s visible on a PET/CT and is showing metabolic activity indicating its cancer.
MRIs are great for certain things like herniated disks in your back. They suck at cancer.
It's not that MRIs suck at cancer. They provide fantastic structural and functional data.
The problem is the specificity of the results and the prior.
A full body MRI by definition will provide detailed views of areas where the pretest probability for cancer is negligible. That means even a specific test would result in a high risk of false positives.
As a counter point, MRS means that you can now MRI someone's prostate and do NMR on lesions you find.
Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as do a analysis that would otherwise require a biopsy. With the raised prior you can be quite sure suspicious lesions are cancerous.
Similarly for CNS tumours. Where fine detail. Subtle diffusion defects can mark csncers you couldn't even see if you cut the person open.
No sensible doctor would give you a whole body CT unless there was a very good reason. That very good reason is probably "we already think you have disseminated cancer". That pushes the prior up.
And less so for a PET/CT. Lets flood you with x-rays and add some beta radiation and gamma to boot!
The danger of an unnecessary CT/PET is causing cancer, the danger of an unnecessary MRI chasing non existent cancer.
> Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as ...
Not a doctor - but maybe start with some quick & cheap tests of their blood & urine, polite questions about their sexual partners, and possibly an ultrasound peek at things?
At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
> At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
Maybe it's a regional thing, but that hasn't been my experience. I've had one MRI and one CT scan in the 25+ years that I've been a full-time employed adult with insurance.
I'd have been happy to sign up for more so I could have proactive health information and the raw data to use for hobby projects.
> The danger of an unnecessary CT/PET is causing cancer
You'd have to be massively overexposed to CT or PET scanning to cause cancer, like in the region of spending months being scanned continuously with it at full beam current.
Even if you don't agree with linear no threshold models for cancers induced by radiation (I don't think LNT is accurate).
It comes down to the scan and the age.
3 scans for a 1 year old? Strongly associated with cancers later in life. 5 scans of a 50 year old? Less so.
The 1 year old has an 80 year run way to develop cancer, along with cells already set in a state of rapid division, and a less developed immune system.
There's excellent reason to think LNT is accurate: at low doses, almost every cell is exposed to at most one radiation event. The dose affects how many cells experience a (single) event, but does not affect the level of damage to those exposed cells. Linearity naturally falls out of this.
To abandon linearity you have to imagine some sort of signalling system (not observed) that kicks in at just the dose we're talking about (not lower, not higher) to allow exposure to one cell to affect other cells.
There's also no good evidence that LNT is wrong. The typical things that are pointed to by anti-LNT cranks are cherrypicked, often involving interim results from studies the full results from which do support LNT, which is evidence it was statistical noise.
> You'd have to be massively overexposed to CT or PET scanning to cause cancer
The mean effective dose for all patients from a single PET/CT scan was 20.6 mSv. For males aged 40 y, a single PET/CT scan is associated with a LAR of cancer incidence of 0.169%. This risk increased to 0.85% if an annual surveillance protocol for 5 y was performed. For female patients aged 40 y, the LAR of cancer mortality increased from 0.126 to 0.63% if an annual surveillance protocol for 5 y was performed.
How are they determining "this cancer was caused by the CT scan" versus "this cancer was caused by the cancer we were originally looking for that was there all along"?
Well, you could work backwards and look at your assumptions.
Why is "We think this person has cancer so we gave them a CT scan and look! Now they've got cancer! It must be because of the CT scan!" the conclusion to jump to?
Please just read this article - https://jamanetwork.com/journals/jamainternalmedicine/fullar...
It's funny that you instantly assumed that authors are stupid and did not think about this obvious pitfall. It's extra funny that you also accuse them of jumping to conclusion without actually reading the article.
> MRIs are great for certain things like herniated disks in your back.
I have had a lot of experience with MRIs on both myself (back and knee [1]) and my dogs with herniated discs. The doctors always make it sound like MRIs are great to confirm what's suspected because of other symptoms like pain, but a point in time MRI alone is not that valuable. Everyone's bodies (including animals!) are surprisingly different inside making normal be somewhat unique. I think what would be interesting is if scanning technology like MRIs could be made so inexpensive and easy that everyone had one done 4x/year. That way it's the differential being checked and I'm guessing it would be way more valuable. Normalization such as this could also lower anxiety around findings.
[1] Even when I tore my ACL the MRI came back only as probable.
Do you know which MRI you used? Not all are equal.
Most MRI are 1.5T powered, and you can’t get fine details until you hit 3T. And there are differences even in the 3T power range. There are higher powered MRI which are mostly only used in research, whilst it is a bit scary thinking about the sheer power of them but a 7T machine doing a full scan of you, would be guaranteed nearly to find anything wrong with you.
When I last looked the full body scans for sale seemed to used 1.5T setup, which seems like a waste. The 3T advanced scans looks much more detailed, but it just depends on where you live - I couldn’t find any around.
My knee and back was years ago, so probably the 1.5T. No idea on my dogs who have had the more recent MRIs. Their scans are incredibly detailed though, so maybe the 3T?
One caveat is that regular PET isn't so good in the brain - there is so much metabolic activity that everything glows. So I get an MRI Brain to go with my regular full body PET/CT (cancer 5 years ago with recurrence 18 months later, currently NED).
I had a CT scan last year for some stomach issues they wanted to look at.
Doctor warned me up front that the odds the images find something that looks weird is high but not to panic because of how many false positives there are when looking inside someone’s body.
While I am happy to report they didn’t find anything serious, I do take slight offense to the following at the top of my results:
Last name, First name: Unremarkable
(Kidding of course but still got a chuckle out of me)
2.5 years in of regular PET scans. At this point, I’m almost humored by what gets flagged as suspicious by the radiologist - usually mosquito bites and stomach bugs (kids in daycare means I’m almost always sick). I have a scan Monday and two weeks ago had a re-excision so there’s a two inch gash healing on my back. This week I got three vaccines. And then tonight my toddler bit me hard enough to draw blood. I had asked the oncologist if it made sense to delay the scan because of the re-excision and he said not to worry because he’d know why there’s inflammation in that area. I’m thinking the bite and the shots will probably get flagged too. I just hope I don’t forget any other maladies or mishaps that might get flagged that I can’t explain.
How often are they finding actual positive hits on the PET? If its so unreliably with regards to false positives why do you continue to have PET scans done?
PET Scans feature areas with blood flow so tumors show up as hot spots for follow up. People who are maybe only feeling off or had one confirmed tumor can have a lot of small tumors spread across their body which will show up clearly on a PET scan.
When my brother was at the end of his run fighting cancer he felt a bit under the weather and managed to catch covid so everyone figured he was feeling bad due to that. The PET scan showed he had thousands of small masses converging into the large mass that eventually killed him by cutting off blood flow to his kidneys. His cancer was an aggressive blood cancer that had stood up to conventional and Trial Chemo drugs. There was no way to treat this but other cancers that are less aggressive can be treated at this point and would be treated differently than a single mass.
In a nutshell it’s that level of visibility that makes PET scans worth it.
PET scans are not really unreliable, they’re just very sensitive and lots of anomalies ranging from benign cysts to malignant tumors show up on them. It’s not always possible to differentiate them without other measures like biopsies, so that’s where the false positives come in.
Getting regular scans to track cancer progression is a different matter altogether, since most of the blips can be eliminated over time and there’s a history to compare against.
Anecdotal evidence to confirm: I had two false alarms from an unrelated MRI scan, and beside wasting a lot of time on diagnosing them - it was also extremely stressful.
My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment,
These treatments are wonderful and it is great that they exist. But many people fail to understand the difference in terms of pretest probability, etc.
I can absolutely see the heavy psychological impact pending biopsy results may have. People are quick to discount these issues when you raise them as a concern, but only if they never went through this stress themselves
Sorry, I missed a key detail. What you are describing isn’t the ‘whole body mri’ I’m referencing by to.
People in high risk situations like multiple myeloma, or various metastic diseases, or system conditions are a whole different category and there is clear benefit to screening them.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
My mum gets scanned a little more frequently than that, following treatment for an inoperable tumour in her lung around five years ago. During treatment she was getting scanned every three months or so, and it was remarkable watching this thing go from the size of a tangerine, to actually expanding a bit and looking "fuzzy" once the drugs kicked in, to being the size of a plum, then the size of a grape attached with a little thin thread of tissue, to being a thing the size of a pea. Now there's a tiny ripple of scar tissue that no-one wants to investigate further, because if it's not doing anything let's not poke at it.
There is a roughly pea-sized "thing" on her adrenal gland that was a bit worrying because anything like that is going to get intimately involved with your lymphatic system and then it's going to metastasise like hell. But it neither got bigger nor smaller in the nearly six years since the first scan, so it can't be that important.
This is one of the great things about the NHS, especially here in Scotland where we have (possibly as a result of the weirdly high levels of cancer) some of the best oncology services in the world.
If we'd lived in the US, the insurance companies would have taken one look at an 83-year-old about to become a grandmother and sent her home with a bottle of morphine to die. As it is, she's doing very well and got to see both her grandchildren start school.
> in Scotland where we have (possibly as a result of the weirdly high levels of cancer)
Interesting, I had no idea and just looked this up[0]:
> Scotland had the highest overall incidence (446 for men and 379 for women per 100 000), and Wales had the second highest rate (450 and 366 per 100 000), compared with 394 and 338 per 100 000 in England and 394 and 345 per 100 000 in Northern Ireland.
Thanks, she had little to no side effects from the experimental immunotherapy drug. She'd said at the outset she didn't want to be a "chemo zombie" having been through all that about 20 years ago (she's had four different cancers throughout my lifetime, treatment getting better every time).
It's fucking expensive, but immunotherapy is really a miracle cancer treatment. We're not quite at "Oh you've just got a wee bit of cancer, we can give you something for that if you see the pharmacist on your way out" but we're not far off.
MRIs are good if you know what you’re looking for, and usually with contrast, which in a situation like cancer where you need to do them often can result in allergic reactions.
In a full body situation, they are looking for mets, and the uptake of radioactive sugar by the tumors will let a PET scan find them.
That’s completely and 100% false. It’s much easier to characterize things on MRI and MRI is indeed phenomenal for cancer! The problem is with screening, not actual staging or follow-up, and whole-body screening in ct and pet/ct is even worse than MRI screening even if you ignore radiation.
The argument for better screening would require that finding those asymptomatic cancers actually improves survival rates. There are several reasonable scenarios where early screening doesn't improve it:
* The cancer is aggressive and resistant to treatment. Chemo/radiation only pause the growth for a bit, but ultimately the cancer keeps growing and the total survival time is the same (only that the patient spent more time knowing they had cancer).
* The cancer is susceptible enough to treatment that it's still curable when it becomes symptomatic and found through other means.
* The cancer is slow enough that the patient dies from other causes before.
Early screening brings benefits only when the cancer ends up causing issues and responds differently to treatment between the "early screening detection" time and the "normal detection" time.
It's impossible to know beforehand which of the scenarios have more weight, specially because we have very little data on what happens way before cancer is detected via the usual methods. We need better studies on this, and for now the evidence doesn't really point out to these large, indiscriminate screenings being actually helpful.
That’s not the correct framing - your assertion first lacks evidence about why we should screen better. In fact, we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Further, the denominator is asymptomatic people who were able to get MRI’s they didn’t need. That doesn’t tell us anything about the normal world.
> we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Even assuming your statement is true, if what is detected is small enough for that there's no reason "treatment" can't just be monitoring it's size with follow-up scans.
> if what is detected is small enough for that there's no reason "treatment" can't just be monitoring it's size with follow-up scans.
This is false—it is exactly what the article is trying to convey. There is a risk to any test, and one of the major risks for imaging is getting treatment for things that would never cause symptoms or require intervention.
If the cancer is vizible in MRI or CT scans, the immune system already failed to "resolve" it and will not do so in the future, at least not without external help.
> If the cancer is vizible in MRI or CT scans, the immune system already failed to "resolve" it and will not do so in the future, at least not without external help.
This is false. A simple google search for spontaneous remission (or honestly anything similar) would show/have shown you this.
I wonder how biased the group is though, is the sample truly representative of the general population or is it a group of people who are already undergoing screen for some other health-related reason?
1. I had a chest x-ray
2. It showed a small dark patch, and my lungs over-inflate.
3. Erring on the side of caution, doctor ordered a lung biopsy.
4. Lung biopsy is painful, annoying, expensive, and non-zero-risk.
5. Lung biopsy turns up nothing. "Maybe you aspirated some food?" We learn nothing.
I don’t understand how you’re concluding that the biopsy shouldn’t have happened from that anecdote? Just because a test result is negative doesn’t mean that it shouldn’t have happened. That’s not how practicing medicine works.
Hence the N=1 I started the statement with. If we had a thousand similar situations and it turned out that in, say, 1% of cases there was a lung tumor, then we could debate whether it's worth putting 990 people through a biopsy they don't need so 10 can find out they have a tumor. Maybe that gives us the opportunity to discuss waiting a month and taking another chest x-ray (which has its own negatives) vs. doing an immediate biopsy.
But we don't have 1000 similar cases. As I said, we have 1: mine. And it turned out negative. So 1 person was put through a biopsy they didn't need, and 0 people found out they have a tumor.
I feel that label is actually deserved. Yes, some cancer types are easier to detect with MRI, in particular inside of a body, but at the same time MRI in and by itself isn't great at predicting all cancer types. How could it help with regards to leukemia, for instance? What exactly could MRI detect here better than other diagnostic tools? One has to keep in mind that diagnosis also takes time - plus the cost; and the overdiagnosis problem which means that some cancer that are not really relevant, are hyped up by MRI to be the end of the world for a patient. So there is a trade-off.
IMO MRI needs to become cheaper; and more reliable too.
Basically half of all men have some early form of prostate cancer. Now that does not show up very well on an MRI, but there are quite a few diagnosis like that that are not necessary life saving.
No? The point of the article, and of the preceding comments, echoing a pretty common tenet of evidence-based medicine, is that frequent full-body MRIs are a bad idea for the patient.
This guy has never heard the term 'scanxiety'. Go ask what it means on a cancer forum. The real OG's are the VHL folks. Bet we have a few here on this thread. Respect.
I have, it's the fault of how medicine is practiced to reduce cost. It's completely avoidable, you can just not tell people their scan results if they have no symptoms and the detection is less than 95% likely to be cancer. This is strictly better than the status quo because the only difference is some people who almost certainly have cancer learn that they have cancer and nothing else changes
Right, the problem in your model is that the doctors do! I am pointing out that this is a problem with the doctors, not the scan.
Scans are a tool, doctors are not allowed to use them rationally because it would be too expensive, so they don't use them. With an ideal doctor, patient outcomes would be better with a scan than without one, but my claim is that doctors are not ideal.
No doctor would order a full body MRI just to throw out the result in 99% of cases, because *it's too costly*
I agree, but they are failing to order scans when the probability of finding anything worth biopsying is low because of cost.
This is so obvious it's crazy, our entire world view is misshaped around saving money.
When you walk into a doctor's office, why do they take your blood pressure and temperature? Why do they look at the back of your throat and listen to you breath?
These are all diagnostic procedures with extremely high false positive rates. The reason doctors do these but do not do MRIs is because MRIs are expensive.
If MRIs were free you would get one automatically every time you go to the doctor.
It’s a great document, I’m an MR tech and we now have something to lean on when we say no to these scans. We can then scan people with problems rather than people with too much money.
Great document? I just read the entire thing, it contains no evidence or justification for their claims.
> We can then scan people with problems rather than people with too much money.
Right, this is what it's really about. MRIs are a scare resource and providers need to manage cost. Fortunately I can afford to pay out of pocket, but I'm just annoyed that doctors are so irrational about this
To be clear, it's up to a doctor whether or not to do a "needless biopsy". That has nothing to do with a scan.
You're imagining that the doctor is required to act irrationally or against the patient's interest. I understand that they do act this way, but I'm pointing out that they don't have to!
You walk into a doctor's office and meet for the first time.
Case 1. You have 3 full body MRIs taken 6 months apart in hand and give them to your doctor. Nobody has opened or looked at the scans yet.
Case 2. You do not have a scan yet
You are claiming case 1 will lead to worse outcomes in expectation. I claim that's impossible because the doctor can simply do the following:
Without opening the scans, email them to the world's best radiologist. Tell that radiologist "only reply if it is nearly certain the patient has an operable cancer with the information available"
Now there are 4 possibilities.
Case 1 without cancer: nothing happens
Case 2 without cancer: nothing happens
Case 1 with cancer: you maybe survive
Case 2 with cancer: you die
The only reasonable objection to this is "that's expensive"
A whole body MRI is low resolution and thick slices, they are crap.
Instead you could get thin slices at high resolution of a body site that has issues or is suspected to have them. Do that instead.
Whole body MR is 5-8mm thick slices at low in-plane resolution. A whole body scan has about 512 pixels over a 50-60cm field of view. Usually it’s even less pixels than this.
Something like a knee, or brain is 2-3mm slices, and high in-plane resolution. A knee is 512 or even 720 pixels over 14cm. It’s vastly better. The difference is stark.
A liver scan or other abdominal organ is lower resolution than a joint or brain, but unlike whole body MR is scanned in multiple planes with multiple image weighting (t1 in/out/fat sat, diffusion, t2, t2fs, gadolinium contrast). A liver scan has thin slices.
Whole body scans generally do two coronal images (stir and t1) then call it quits.
Yes the machines should definitely get better, but I recommend you do get it if the cost it truly zero. Based on the data in the article it is still worth it despite the low resolution!
Sorry, I edited my above comment to remove references to myself.
For clarity, I’m an MR tech and I can get scans of myself if I want to.
I generally don’t scan myself as it gets messy fast. If I had concerns and for some reason couldn’t get a proper imaging referral, I’d get a scan with small, good coils with high element counts (not body coils like whole body imaging uses) and scan individuals body regions.
It is not only money, machines and doctors are also a limited resource.
The other bit is that no one follows your protocol, everyone looks at the scans, finds reasons to worry.
Then you have the choice between unnecessary biopsies and psychological stress.
I kinda agree with you and I understand your point but I also think there is a social-ethical reality that if a doctor finds something they must treat it. The two options are 1. doing nothing, or 2. reducing cancer risk and you get unnecessary biopsies.
You're thinking of this as there being an objective positive utility for not dying of cancer and a objective negative utility for biopsies, and there being an objective optimal "rational" tradeoff that the best radiologist can optimize for to get their "nearly certain" detection threshold.
But frankly - the tradeoff for the value of a human life is perhaps the most uncertain thing one could choose. It lies in the eyes of the patient if the worry and time associated with a false detection is worth their reduced chance of death. The ethical uncertainty expressed in the OP - are these unnecessary biopsies worth it - is warranted.
You a-priori do not know if you have cancer. The case 1 branches are:
Case 1 without cancer: you're a guy that knows more than doctors because you're the "I have 3 scans on hand guy", so as soon as you open the scans and the doctor says there's a mass, you will say 'OK what can we do???' And then you had a worthless biopsy.
Case 1 with cancer: you saved the 1 week it would take to schedule the new scan and get results and you're basically in the same situation except one week earlier.
That's not how it works. Without the history of scans spaced out in time, they would typically need a biopsy. Multiple scans over time shows change and growth and improves the likelihood of an accurate triage
And for the first part that doesn't happen in my scenario before the doctor doesn't look at the scans
Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them. Yes, right now MRIs are expensive and false positives are common, but if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
There's a softer component to healthcare which is that people can overreact to medical results. If a doctor administers a scan, finds a handful of likely benign things but wants to administer another scan later on down the line, I'm probably much more likely to look for a second opinion that tells me to cut them out (even if it may not be medically necessary) than trust my doctor that "it's probably fine".
It's probably more accurate to use a software analogy about performance metrics. We measure random request spikes now and again that strain the system. It's probably fine, but later on down the line, something could change that results in an outage during one of these spikes. Do we proactively fix the problem even if no change is expected? Or do we wait till there is definitely a problem before taking action?
But surely this would decrease as we learned more from more frequent MRI scanning. Doctors and patients would be less likely to overreact, and we'd settle in on something better?
But if you’ve never looked at the log before all these WARNINGs might be normal operation. It’s not turning off logging, it’s saying log at ERROR level.
Not to mention the malpractice risk and potential for extra income, which -- depending on where you live -- may strongly (if subconsciously) influence your physicians interpretations and recommendations.
Do you think a doctor is more likely to call something "possible cancer" and recommend that you either have a specialist do a biopsy (keeping in mind that many of these will be... hard to reach) or at least have a follow up MRI in 3, 6, 9 months?
Or tell you it's "pretty unlikely to be cancer, I don't think we need to worry about it" and then get sued for 20M when they are wrong about 1 in 100 cases (not to mention missing out on all the potential income from above).
At least in the US, the incentives here are grossly misaligned.
The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality.
The reasons are complex, but the short answer is that cancer treatment is extremely hard on your body, and even if you don’t treat, stress can literally make you sick. I recommend reading The Emperor of all Maladies if you want to really get a sense for how delicate the problem of early screening is.
I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here.
The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects.
What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice. It shouldn’t be up to a health economist to make that judgement.
But who will pay for the hundreds of thousands of screening MRIs, along with the large number of incidental results that will require some sort of follow-up? Many patients will seek second opinions if not recommended to "cut it out", with additional costs also for the complications resulting from unnecessary biopsies. US medical care is already tremendously expensive; adding all of these costs will break the bank and for no real benefit.
> What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice.
What you're failing to capture is that this is a hard problem because it's both an individual choice and a collective one as well. Those "terrible side effects" might actually end up killing someone. You're choosing between a high-chance lottery on a small population or a low chance lottery on a far larger one. It's not that simple.
I appreciate that, but do wonder, if this is an issue with too much data or how we act on that data. In other words, could there be a future where we do have tons more data, but also use the data in such a way to achieve an overall better outcome for patients?
Maybe, but there's a human element that can make things worse too. Take prostate cancer as an example. Most men die with prostate cancer. Most men don't die _from_ prostate cancer. It isn't usually aggressive enough to matter. Most people aren't zen enough to accept that though, so just knowing that you have cancer can add stress to your life with measurably bad health impacts from the resulting hormonal changes (reduced immune function, impaired sleep, increased clotting tendency, slower wound healing, etc).
Ultimately its a balancing act between what we can know and what we can do about it. If you can’t treat a cancer (or your treatment is not effective, cf the radical mastectomy) then knowing who has it doesn’t help. As technology progresses and more cancers become readily treatable, it will make more sense to do early screening, and potentially full body MRIs.
But right now it is likely to cause a huge waste of time, resources, and yes, human lives to know about every little lump in your body.
Then they should decide not to treat certain things and have better criteria around that than choosing to bury their heads in the sand and letting people die out of their ignorance.
> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
> To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
The analogy is rather something like this: your downtime detector is not just a "ping" but a full web browser that tests everything and it sometimes flags things that are not actually issues. So you don't turn it off, but you only use it when you have another signal that indicates that something might be going wrong.
> Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
This is the main reason. Well technically the opposite of the main reason but more or less it's the same. MRIs are extremely high fidelity nowadays and as a result it's really really hard to read an MRI. Every person is different and there's a lot of variations and weird quirks. You get all the data rather than clearly identified problem areas like you get with say a CT w/ contrast, etc.
That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
> That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
How? How do you establish baselines? How do you build a classification of incidental findings? It's very possible that you'll find a lot of types and not a lot of representatives of each type. And then you have to correlate that to actual clinical results, but the population will be so heterogeneous that it'll be really hard to find an actual result.
It's not just "let's throw more data at the problem".
When I say establish baselines what I mean is to establish baselines for the individual.
If you have records of the locations and sizes of various atypical structures and forms throughout the body going back for years and all of a sudden one of them starts changing in size at a rate disproportionate to its history, that's probably cause to dig a little deeper.
It's certainly not "throw more data at the problem". Instead it's about giving the data a time axis with some decent fidelity.
> and all of a sudden one of them starts changing in size at a rate disproportionate to its history, that's probably cause to dig a little deeper.
That sentence is doing a lot of heavy lifting.
- What's "disproportionate to its history"? Obviously something going from 1mm to 10cm is worth checking out, but what about something going from 1mm to 2mm? Might be a tumor, might be that the position is just slightly different.
- What about other less measurable factors? Example, border features. That's harder to measure and things like movement or different machines can change how the borders of a feature look. How do you know what's a baseline and what's not.
- How frequently do you run these scans? It's likely that if something "starts changing in size" suddenly it will start giving symptoms before you have your next scheduled scan.
> It's certainly not "throw more data at the problem". Instead it's about giving the data a time axis with some decent fidelity.
It's definitely throwing more data at the problem, and you're assuming that it's viable to give "a time axis with decent fidelity". MRIs are much more complicated to interpret than people think, and screening is a much harder problem too. There are a lot of studies testing MRI imaging as a screening technique (among other techniques) and they don't always show an increase in survival rates.
We do not have a lot of MRI data. The average person probably gets a couple MRIs in their lifetime, and this is biased because we wait until something is clearly wrong to get the MRI. If you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong with them in the same general area and gets an MRI for that, and then just by chance also has the early stage cancer at the same time.
> we wait until something is clearly wrong to get the MRI. f you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong
Not always. There are bunch of studies for MRI screening in high-risk populations for specific cancers. There are scoring systems for a lot of them based on imaging features and they do find asymptomatic cancers.
In fact, if you add low-risk populations to the studies used to design imaging scores, you might end up adding more noise and making the study more difficult and the scoring less accurate.
Additional diagnostics can also be very expensive. Articles like this don’t seem to understand the overall costs to a health system with decisions like these. And that cost eventually does go down into the pockets of patients one way or another.
I think the point of the conversation is that if we take the predatory capitalism out of the way, using MRIs could potentially be a net benefit overall for everyone.
I'd argue that malpractice risk has at least as much negative influence on a physicians judgment.
It's perceived as much less (medico-legally) risky to "do something" (or more often "refer the patient to someone else to do something") than not do something.
OECD data (most recent available, around 2020–2022): MRI units per 100K population: United States ~3.6, Canada ~1.0, United Kingdom ~0.7
I would argue that getting "predatory capitalism" out of the way has sharply curtailed MRI availability where that's been tried. Maybe we should loosen the leash on capitalism a bit to get better care...
I've seen instances where this is used as an excuse for what is, ostensibly, a trick to dimiss people using something that sounds vaguely professional. Like when doctors say they don't want to do additional x-rays because of the risk of radiation exposure, nvm that if it comes out slightly blurry they'll ask to redo it, or if you're cautious about it initially they'll tell you how it's not big deal and there's more radiation in a cluster of bananas.
Biopsies, radiation from additional scans, surgery, treatment for cancers that would not have developed further.
A lot of potential harms are at a societal level as well—from a public health perspective, if everyone starts having regular MRIs that produce incidental findings which require followup, you’re suddenly tying up lots of resources that would otherwise be available to actually-sick people. A person with symptomatic problems whose treatment is delayed because they can’t get an appointment because the specialists are booked full with incidental findings, that person is indirectly harmed by this.
The radiation from CT scans is not especially concerning at an individual level when there is a compelling reason for it, but, if we’re suddenly doing tons more to investigate incidental MRI findings, there may well be a point where those scans are causing a significant amount of cancer overall—a recent study suggested, I believe, that CT scans may be responsible for 5% of cancers already.
Like when someone has an anaphylactic reaction to the contrast dye for their CT?
Contrast-induced nephropathy?
Gadolinium accumulation in the brain doesn't sound good for you...
Although I think this argument is usually talking about the risks of the resulting procedures (eg an injury or complication related to a biopsy done for a finding on imaging).
The United States Preventative Services Task Force[1] reviews studies and meta-studies to make recommendations about screening procedures. Their ratings are used by Medicare and Medicaid to decide what's covered and for which patients. In turn, many private insurance companies cover the same procedures. The USPSTF explicitly doesn't consider cost in their recommendations. Most often, they look at whether a screening reduces mortality rates.
But you're not having cancer checked out, you're having a "spot" or a "nodule" or something checked out.
And the person that's making the recommendation on whether or not to check it out may get sued for $10M if they tell you it's probably nothing and they're wrong, but have no harm come to them if they tell you it's worth having some other doctor do a biopsy.
And they might make an extra couple hundred bucks every time you have to come back and see them to follow up on this spot.
And the radiologist interpreting the MRIs... the same perverse incentives regarding how they interpret a "spot."
Insurance-based medical systems mean the patient has transferred responsibility for saying no to those actually paying the bills. They have to draw the line somewhere.
> ... if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
And if there's one thing where AI models really do already excel at it's classifying and noticing patterns.
Many dermatologists (not all of them yet, at least not in the EU), for example already have software classifiers using pictures of one's skin and helping guide diagnosis. I've lots of moles/nevi and freckles on my skin: I'm one of those Gen X kids raised by parents that had no idea that sun exposure and sunburns was a bad thing so I regularly get warning shots and my body, especially my back, if full of scars for for my entire life dermatologists have regularly removed concerning little buggers and sent them to the lab for further analysis.
Nowadays my dermatologist is helped in her classification by hardware/software.
I don't see why that wouldn't be the way forward for full scan MRI: they'll begin to be more and more hooked up to AI classifiers.
It always takes time: it's not as if the tech comes out and in 48 hours every hospital/physician is equipped with it.
It's literally the future is here (classifiers helping dermatologists find concerning nevi), just not evenly distributed (many dermatologists still don't have access to these latest machines).
I can't imagine this taking strong hold in the US unless it shields physicians from legal consequences of false negatives or produces enough false positives to ensure revenue doesn't fall.
I don't see any way that the hospital systems running healthcare in the US would embrace a technology that reduces false positives (income) without decreasing false negatives (risk and lost income) at least as much.
> Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them
More and more European countries are currently adopting Lung Cancer screening programs. It's usually limited to people with a certain amount of cigarette-pack-years, but still gives the opportunity for driving more of the innovation you're talking about. I think the main challenge at the moment is that nothing in healthcare is prepared of looking at those scans effectively, a radiologist has full medical education + additional specialization - without effective procedures you'll never be able to provide full-body scans with any meaningful impact.
It’s expensive because superconducting magnets cryogenically cooled in liquid helium are expensive to build and run. No amount of demand signal will overcome that reality.
Not just cost also time. When I had my scan it took 45 minutes and two trained nurses.
Ofcourse in America poor people don't have access to healthcare so it's a lot easier. But in a universal healthcare system everything has to be rationed.
Most people do have things “wrong” with their body, but they are asymptomatic. The human body can and does cope with a certain amount of failure and/or anomaly as a part of normal operation that we otherwise consider healthy.
The problem is that this information is often not actionable. An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems. The way the body naturally responds to problems doesn’t always look perfect on a scan but if it results in no symptoms it is the best result. And for most asymptomatic findings, taking an invasive next step has more risk than the finding itself. And these findings will always be in the back of the patients head, whether relevant or not, and might complicate how they seek care for other real issues later on.
> An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems.
Its the doctors doing this, not the MRI.
There's this weird definition switch that always happens with the "overdiagnosis" defense where the information gets blamed for the overdiagnosis. An MRI doesn't provide any diagnosis in any sense of the definition. A doctor does.
Claiming an overdiagnosis defense is essentually implying the medical industry is worse for most than doing nothing.
Yeah, any doctor worth their salt is going to be diagnosing you based off of the MRI results and some other evidence.
But in the scenarios this article is talking about (Prenuvo, et al), these aren’t scans ordered by a doctor, and there is no other evidence. It is just a patient getting some MRI findings of unknown clinical significance dumped in their lap.
The problem isn’t an overdiagnosis by doctors. The problem is that there’s no doctor diagnosing anything in these instances.
Same logic as not treating the cancer of an 80 year-old as a heuristic rather than looking at the health, genetics, and epigenetics of the individual beyond the chronological age. Whatever happened to "personalized medicine?"
This article sees methodological failure, I see training data. Training data that could ultimately be used to refine low resolution scans into targeted high resolution scans as needed driving down costs and driving up accuracy. We've already demonstrated AI upscaling, what's the blocker to doing the same for MRI?
And finally, who are any of us to tell people what they can do with their money? China has these things down to $70. And they're leaning in hard on improving them. Cue obligatory China cuts corners blah blah blah. Sigh.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
So a bit less than 1.8% of the time in this study
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer.
That's 2.0%
Note that this doesn't mean that 1.7~2.0% of people have cancer without knowing it. It could be more:
> A negative scan doesn’t mean you’re disease-free. Some cancers and conditions simply aren’t visible yet or aren’t reliably detected on a one-time full-body MRI."
But also perhaps less, in a way:
> "You're finding something that never would have caused you any problem in your life, and in cancer, we call that overdiagnosis," Vickers says.
Yep, I have experience with both. It found cancer for my wife and she was able to treat it immediately. Fully recovered.
It found a weird spot on me that turned out to a pancreatic rest.
The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year . We knew nothing was guaranteed but we wanted to do some tests.
> The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year .
Interesting. If it's not too personal, would you mind elaborating on the kind of life decision you were making?
I have never heard of anyone getting checked up for cancer before they make an important life decision. I mean won't a cancer diagnosis disrupt your life anyway?
We were buying a sailboat(we actually did it). Wife got diagnosed with cancer. We talked with doctors about treatment, felt confident with catching it so early.
Purchased the sailboat, we live on the sailboat with our two kids, two dogs, and two cats, 6+ months out of the year.
What you can't plan for is shit that happens on land. We came back in June 2025, my wife was stopped at a red light and got rear ended by a dump truck. That has put a pause on our sailing life. But we should be getting back out there soon.
There's a theory that the first-stage cancer is way more common than we think, it's just doesn't develop further most of the time, cause no symptoms and remains undiagnosed throughout the lifetime.
There's some support for this view because agressive screening for thyroid and prostate cancers increases the number of surgeries a lot but doesn't seem affect the mortality rates.
Risks from a surgery are non-negligible, if you perform it to treat a low-risk condition it may be a net loss in the end.
So you're technically right about the "early-detecting" part, but the "much easier to treat" step is problematic because it's unclear what a net-positive treatment looks like for low-risk cases. Probably it comes down to yearly monitoring of whatever was detected, not the actual treatment.
Yes, you could early-detect something, but the likelihood of this thing being life-threatening are extremely low. If you choose to manage this thing aggressively anyway, you have to undergo more invasive testing (e.g., biopsies, surgery, anesthesia, etc.) that all have small risks of catastrophic events. In most cases, the risks of more invasive testing outweigh the risks of just not pursuing any further workup.
Nothing in medicine comes for free—everything is a tradeoff.
> Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
It could be. It could also be the cade that you undergo invasive surgery for something that would have never caused you problems within your life. The problem is that cancer isn‘t cancer. Even if it originates from the same tissue, some tumors behave very different from others.
Yeah a 2% risk of having something which can easily kill you and is very expensive to treat, especially if you're not elderly and still have lots of life ahead of your, is not exactly trivial. I would want to know about this
Doctors here are cognitively captured by a system designed to limit cost (and that's mostly a good thing)
But scanning frequently is overwhelmingly good for the patient. The problem is the doctors. Imagine two possibilities.
1. You scan every six months and a doctor reviews your scans but never tells you anything no matter what
2. You scan every six months and a doctor reviews your scans and only tells you results if you have an obviously growing mass that has a probability greater than 95% of being cancerous
Obviously #2 is better for the patient than #1, but #1 is equivalent to never testing if you ignore cost.
So the actual reason we don't have effect frequent scans combined with effective diagnostic techniques is cost, and doctors cope with this reality by saying clearly wrong things about "over diagnosis". It's a local minimum of the payer/provider dynamic that has nothing to do with scans per se.
Why is it good for the patient? I think that to claim this, you'd need to show a difference in outcomes.
Here, you have a tool with a ~100% false positive rate, so if we start administering it to everyone, it will almost certainly cost lives. Botched biopsies, unnecessary treatments, other complications. Not to mention the huge cost that would divert money from other welfare programs. So you need to show that when it actually detects something, it saves at least as many lives. And I doubt that's the case.
I wouldn't argue we should roll this out to everyone. But I am glad it exists. I commented earlier in this topic about how it caught cancer in my wife at the age of 44. She didn't have to go through chemo or radiation treatment because it was caught so early. Surgery removed the whole cancer.
Additionally for me, I have a scan that shows what my body currently has. I had something show up that I did get a scope to check out that was a pancreatic rest. No big deal. Now, if I ever have another MRI and somethings is somewhere else, we have a baseline to compare against. Everything is a risk calculation. When I did my MRI, I also had other procedures done like a heart calcium score.
I will get a little more personal. We didn't do it out of the blue. My wife and I decided we want to live on a sailboat. That was a big purchase for us and boats take a long time to sell. We didn't want to commit to such a purchase then 1 year later find out either of us had cancer then we have the stress of cancer and the stress of trying to sell a boat.
I would never suggest everyone do it, but I am happy we did.
I’ll give you a counter example. I had an MRI of my neck for unrelated reasons. It found a thyroid nodule with suspicious characteristics. Incidentally I had had an MRI of the same areaa few years before and it wasn’t there.
So I had a biopsy. Which was equivocal also.
So I had it out which involved removing half my thyroid. Turns out it was a cancer but like the least serious kind, in fact the classification of it as actual cancer has gone back and forth over the years
But my other half of my thyroid couldn’t produce enough thyroid hormone, and now I have to take thyroid replacement the rest of my life to start alive
Also the surgery affected my voice and I sound like RFK jr now.
I clearly suffered some harm, and even after having the thing out, it’s unclear if that was beneficial at all. A large proportion of these kind of tumors quit growing and never do anything bad. But some do. So who knows.
No. To argue for the benefit of the procedure, you need to show a difference in outcomes. Not that it can detect something, even if it could (which whole-body MRIs clearly don't). That the detection improves your chances of survival.
If you have an growing mass in your body, then if it's cancer, after a year, it might be too late for treatment. Or it may turn out to be nothing: a benign tumor / cyst / fat deposit in an unusual place. Or it may be slow-growing prostate cancer that you can live with for another 20 years, and maybe it's the chemotherapy that will do you in. It's really not that clear-cut in medicine.
To give you have another example: let's say that the risk of appendicitis in people who have an appendix is 1%. And the risk in people who had an appendix removed is 0%. Does this justify proactively removing the appendix? No, because the consequences of complications are much higher than the harm you're preventing. The same applies here: detection, even if 100% accurate, doesn't mean anything. You need to show that what you do with the result actually helps.
With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies
Without my change: many of those 95% die, the 0.5% do not get useless biopsies
And the beauty of this is you can pick the percentage!
> If you have an growing mass in your body, then after a year, it may very well no longer make a difference whether you treat it or not. Or it may be that you would have lived another 20 years just fine
This is just wrong for many parts of the body. In your brain? Your lungs? Growing for a year between 3 scans 6 months apart? Extremely unlikely to be benign
> The same applies here: detection, even if 100% accurate, doesn't mean anything. You need to show that what you do with the result actually helps.
This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
> With my change: 95% of people who are shown scans have cancer and are treated earlier. Without my change: many of those 95% die
Why? What happens if the cancer still doesn't respond to treatment even when detected early? Or, to the contrary, if the cancer also responds to treatment when it starts becoming symptomatic?
That's why we have studies to understand if screening is a good practice or not. It's not that clear cut.
> With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies Without my change: many of those 95% die, the 0.5% do not get useless biopsies
You assume that treating cancer automatically improves the outcome. Treating cancer often kills you, so treating a non-fatal tumor can easily be a bad decision. And a lot of the tumors found by agressive scans are like that, but we don't know yet how much exactly and how to tell one from the other. It's a new question that requires decades-long observations to answer.
> This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
You're saying it as if detection somehow cures cancer, it doesn't.
> You're saying it as if detection somehow cures cancer, it doesn't.
No, I didn't say the detector would cause cancer to be cured.
I said fewer people would die with no downsides. If treatment is sometimes harmful then the detector also fixes that, you'd never treat people without cancer
No, the detector doesn't fix that, that problem is not treating people without cancer. The problem is treating people with cancer that won't kill or harm them during their lifetime. In this case even a low risk treatment becomes harmful, let alone cancer treatments.
Whether treatment is net harmful or not depends on the level of the risk with no treatment. If you apply treatment with 15% chance of severe side effects to a tumor that will kill the patient with 50% chance in the next five years, of course it's net positive. If you apply it to a first-stage cancer that has 10% chance of progressing to the second stage, the very same treatment will be net harmful.
So no, most cancer treatments aren't net harmful now, but they likely will be in a world where your programme is implemented. Even something as "simple" as biopsy has mortality rates far from zero. Applying it at scale may not have the effect you expect. And surgeries and chemo are much worse.
But do you see how crazy that sounds? If we know the numbers, we would just not do the treatment in those cases.
And in reality it's not actually close like this. Early treatment is so overwhelmingly better than it completely dwarfs all considerations of biopsy risk.
Late stage lung cancer has less than half the 5 survival of early stage, and around 50% of lung cancer detection is late stage. That's around 30000 lives you could save every year from just lung cancer.
Let's say you don't protocol for all adults. Typically post CT or PET at most 10% get a biopsy. So let's say we increase the false positives that lead to CT or PET by X% of adults. That's 270M * X additional biopsies. Lung biopsy mortality is under 2%.
So the worst case you need a false positive rate under 5% for this to he net beneficial for lung cancer. That's low but with 3 scans 6 months apart and a good radiologist, it's not unreasonable
I believe I've assumed the worst case for all the quantities. In reality the addition screened people would have much lower CT detection rate than the background population, and biopsy mortality has been decreasing. Plus you can do this for only people above 40 where the benefits are higher
Yes, IF we know the numbers, that's the whole problem. Unprompted full-body MRI scans turn up a completely new probability distribution. We CAN'T know the numbers as of today, it takes decades of controlled studies to get them. (Which is exactly what doctors advocate for)
Even for something as studied as colon cancer it's still controversial whether mass colonoscopies are better than occult blood tests. US sticks to the former, Europe to latter. US have higher rates of polyp removal, higher rates of cancer detection, higher rates of surgeries and ... higher mortality rates than EU. Why this happens is being studied today, there are some early results. What is absolutely clear though is that higher detection rates don't automatically lead to better outcomes, it can easily be the opposite.
Or take something as simple as sunscreen. It's well-known that sun exposure for light-skinned people can cause cancer and sunscreen is advised. A few multi-decade studies have shown that while it indeed eradicates the skin cancer it also shortens the life expectancy by a few years.
Primum non nocere, doctors and scientists are unsure whether sunscreen should be applied at scale and you effectively call for mass biopsies and surgeries.
So if this is true, it seems that we must accept that many people will die of cancer we could have detected and cured with frequent scans, because doing frequent scans will overall cause more harm to people who didn't need treatment. So the overall death/harm rate would be worst with more frequent scans?
Isn't that then just a problem with the scan and diagnosis? With more frequent scans it seems highly unlikely that we wouldn't improve this process and end up in a better place.
When there is low prevalence of a condition, but a non-zero false positive rate of a test, the false positives generated by universal testing can in fact be a net dis-benefit (worry, invasive further procedures, etc) to the patient population as a whole, regardless of cost. This is a well understood statistical phenomenon, and is carefully considered by healthcare systems when advising on testing.
As if there was an easy, foolproof and precise way to calculate these probabilities. "Just only alter the patient when it is appropriate" he said. You can solve all the world's problems this way, just "always do the right thing". Reality, unfortunately, is more complicated.
What if in reality the doctors can only say if the probability is above 60% or not? What if some doctors are better than others at estimating probabilities? What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
> What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
It's this one
It doesn't matter that some cancers are hard to diagnose. What matters is that some are not hard, especially if you have multiple scans spanning several years
Did you know optometrists now scan your retina during ordinary eyeglasses appointments? They didn't do this in the past because it was too expensive. But optometrists cannot diagnose or treat based on these scans. They refer you to an opthamologist.
Some day your PCP will do the same with MRIs, but only once they are cheap. For now only rich people have this luxury
Tons of diagnostic interventions have been scaled without strong outcome data. For example many clinics now do fractional exhaled nitric oxide (FeNO) tests because they are safe, fairly cheap, and patients often pay directly out of pocket so they are easy to make money on.
But the evidence for the diagnostic usefulness of this test is extremely low, multiple meta analysis have concluded.
The reason FeNO tests are done but not MRIs is because FeNO tests are $40
Your case #2 doesn't have nearly enough information to say whether it's obviously better for a population of patients. There are a lot of other variables you would need to know:
- The accuracy of detecting a mass
- The true distribution of masses in the population
- The likelihood that of falsely detecting a mass in the same place twice (you seem to implicitly assume that false detections are uncorrelated with each other)
- The likelihood that a real mass is cancerous (you stipulate that this is 95% in your scenario, but you don't say what other factors are used to determine this - as opposed to just knowing that there's a mass that grew.)
- The positive effect of treatment in the case of true-positives.
- The negative effect of treatment or further diagnostics in the case of false-positive.
Saying that doctors are lying about over diagnosis to cope with the fact that diagnostic techniques are too expensive is absurd. They have to actually make decisions in the real world, where your two neat little categories can't be known even if they hypothetically exist.
Can someone ELI5 why false positives on a MRI are so bad?
From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight.
At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups?
I get that ideally we'd have a crystal ball with 0 type I / type II errors but short of that, why is a noisy predictor bad?
> At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months
If a doctor even _hints_ there might be cancer, the patient will have a terrible 6 months (with actual, measurable negative health impacts of the added stress). Also, at some uncertainy-level (say, 10% chance of cancer) the doctor _has_ to say something and has to schedule expensive followups to not risk liability, even though in 90% of the cases it is not only unnecessary, but actively harmful to the patients.
When, on average, the cost of the screening + the harm done by a false positive outweighs the benefits of an early detection, you shouldn't do the screening in the first place.
This seems super dumb to me. If the test detects cancer that doesn't need treatment, don't treat it!! It's still better to know it's there and that you need to monitor it.
> Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time,
Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
My parents are doctors so I’m very used to giving them all the data and pushing decision making down to them. Almost all of the time there is no action to be taken. But this built a certain habit that I realized is not conducive to medical care in the US.
I once told my wife that it’s better if she just passes all information downstream and then lets the diagnostician do the diagnostics.
During her pregnancy, at antenatal monitoring, when asked the routine questions I encouraged her to mention everything and so she mentioned a slight twinge in her chest (“it’s probably nothing, maybe something I ate”). She was hooked up to the monitors and so on but this was a sudden moment of panic for everyone but us. The nurse called for a doctor, there was an EKG machine brought up, all sorts of honestly nonsensical reaction given the data.
I realized my mistake soon after. There’s the obvious legal consideration, of course, but the real magic lies in the fact that no one gives full information so if someone sends you a signal they assume it’s crossed some threshold to significance. My mistake was in being a non-normative participant here, akin to someone who drives straight on green in a land where a green light means you first let one person turn left before you go.
Anyway, patients are supposed to perform pre-diagnosis in the US. And you’re not supposed to show your doctor things that they will then act on. You should first apply Bayes yourself and then give the info to the doctor here because they won’t use Bayes.
> Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
I think what's happening here is that the smoke detector is indicating the possibility of fire, but the toaster is always being immediately doused in water. Which as we know would cause more damage than good unless there truly was a raging inferno.
The suggestion here seems to be moving the smoke detector to somewhere where there's a higher chance of it ringing means a higher chance of a damaging fire. Which seems quite reasonable.
The question is how can you know if it needs treatment or not. I guess you either need to do a biopsy, or check if it's grown after N months (leaving patient scared and anxious during that time). Neither are great if most cases end up not needing treatment.
If the test provides you zero information about whether it needs treating then it was never a useful test. Presumably it's more like "there's a X% chance this needs treatment". In which case you just set reasonable thresholds for X. E.g. if it's 5% you monitor it, 10% you do a biopsy, 70% you operate, etc.
This is much more sensible than just not testing at all and letting people die from cancer.
> leaving patient scared and anxious during that time
This seems to be the actual motivation. We don't want to scare people with test results so we're just not going to test them. I think that should be up to the patient.
> This is much more sensible than just not testing at all and letting people die from cancer.
This is not what happens. You're assuming that if the cancer does not get detected by the screening then it never gets detected. What actually happens is that the test gives information that might actually be redundant and obtainable in less risky way. What the studies are showing is that waiting until there are other, more specific signs and symptoms of the prostate cancer results in the same survival rates.
See https://pubmed.ncbi.nlm.nih.gov/38926075/. I was not aware of the ERSPC which came out late last year and gives better outcomes for screening, but overall the evidence is not super clear yet. There are possibly certain groups that can benefit from PSA screening more than others. Also, modern, more effective treatments might allow for later diagnosis with the same clinical results.
Because the patient is usually unable to handle such information correctly (the medical system sometimes too). And the whole-body-scan type of tests additionally pre-select for the high anxiety types.
I pay an extra $60 a year to have my ophthalmologist take a digital image of my retina. It comes back as normal every year, but if something does change we can diff the image against the baseline.
Maybe I don't want to look for cancer right now but if I spend $1,000 every 5 years to take an image for later use... isn't that useful?
Yes, and it seems like its purposefully ignored in the "body scan" debate. full CT scans would be more problematic, and MRI's (especially no contrast ones) don't pick up a lot of things... but having annual comparisons over a few years would likely fill in some of those gaps. literally and figuratively.
Might be, but in the context it's also worth asking what better options you have for your health with that $1000.
(for some people that question may not apply, of course, but at a population level it does, and we have population-level questions about effective use of MRI time.). And if there's something better, you should spend it on that and then ask the question _again_. So it could be that getting a whole-body MRI is something like $30k down the list of best ways to spend money for improved health.
I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
> I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
Spending 1k on a gym membership and more fresh vegetables would be a pretty high return on investment, if one isn't in shape and eating healthy already.
One important point is that many people die WITH cancer but not OF cancer. So even for the 1.8%, only a fraction of those people were going to die of the disease (or even suffer significant symptoms) - the rest were just going to die of natural causes anyway.
But now you've found it you pretty much have to remove it, which has significant quality of life implications.
Age is a big factor in the with/of cancer factor. If someone is 80 years old then there's good chance it won't be cancer that kills them (assuming they aren't already in a late stage).
But if you are 40 and you have cancer, there's a good chance you'll die of that cancer if it's left untreated.
I'm personally of the opinion that cancer screening should happen earlier for younger people and less frequently for older people. Like, if you hit 80, there's really basically no reason to screen for cancer.
It does, doesn't it! This is basically the reason scepticism in screening has risen (amongst scientists and medics, not the general population) - research seems to show that screening catches much more cancer but doesn't save many more people.
Rohin Francis does a good video on it, which you don't have to watch because it has references underneath you can click straight through to (the video is good though): https://youtu.be/yNzQ_sLGIuA
I am frustrated by this because it seems obvious to me that "more data == better" but I guess it makes sense if you think of the scans as having high amounts of noise, and us having a poor understanding of the system we're monitoring (this never happens in tech, of course :)).
From the statistics on autopsy and other accidental discovery, it seems that more than 30% of the population has some cancer by age 40 that would never impact their life left untreated (mostly thyroid, prostate, and surprisingly-for-me, breast cancer). Regular widespread full body MRI might catch these, but the effects of treating (e.g.) prostate cancer are so terrible that most would be better off ignoring it.
Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans? It seems like that addresses much of the harm that a false positive can cause (invasive biopsy leading to complications) while maintaining most of the gains (still very early detection).
The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something off. But you can‘t really reschedule everybody constantly, as that would entirely break the concept.
"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper.
So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much.
Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
I totally agree. US healthcare is broken and costs aren't tied to the reality of how expensive something actually is. I have very high hopes that modern medicine is in for a massive disruptive change where things like full body MRI, along with analysis, could be done very cheap and with no admin overhead. In that model 'we see something we aren't sure of. It is probably nothing but to be sure we want to do follow-ups' is far less of a problem.
A lot of this however is how it is discussed with the patient. Discussions about the likelihood of there being a real issue when something is seen need to be clear and informative without being alarming. 'We did a routine scan and these often show transient artifacts that turn out to be nothing, but in an abundance of caution we want to do a followup' is totally different than 'we saw something we are concerned about and need to do a followup'. How things are messaged really matters.
> MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
How would this work?
I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2.
I can also do an MR scan. It took a fair bit of training and the scanner and scan room cost about US$2 million. Service contracts on the scanner, scan room, chillers and required staffing utterly dwarf the cost of the scanner over its lifetime.
The scan takes 20-75 minutes. Then the images get sent for reporting. Unlike a blood test, reporting isn’t automated. Even if it was, how could availability of MR ever be similar to a blood test?
> I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2.
This depends on a blood test. Bacteria cultures or PCR tests still take more time.
A mid-range scanner costs $500k, the room itself indeed might cost more. Just as real estate. Scanners are just not scarce anymore, there are even sites that sell used ones: https://prizmedimaging.com/collections/mri-equipment (I now want one in my backyard...)
So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible.
A full-body scan is about 1 hour. But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes. So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session.
This is literally in the "blood test" expenses range.
> Unlike a blood test, reporting isn’t automated.
Radiology readings is one thing where AI is already making inroads. And radiologists can be located anywhere, it's a perfectly remotable job.
> Even if it was, how could availability of MR ever be similar to a blood test?
Yeah, indeed. How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building?
Mass production happened. And this time it has taken the industry completely by surprise.
The Skyra is end of life and the ones I know of are getting pulled out. Too old. The generation after it is getting on too. The new generation will appear next year. Likely ‘dry’ magnets - low helium usage. The Siemens 1.5T has already had this upgrade.
> So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible.
A service contract is expensive and also required. I’d expect them to be up to about US$75-100k a year. Coils are US$10-20k each and a scanner has about 10 different ones. We blow about one a month across our scanners and get them replaced. Various things break, and it comes in waves. In recent months: the body coil blew (this is a big deal, $150k?), gradient amp, amp cables, helium expansion vessel, vacuum pump, bore screen, knee coil, another knee coil. The service contract covers all the repairs.
>A full-body scan is about 1 hour.
You can do them in 30-45mins, improving the business case.
But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes.
Doing a real scan of a body site is vastly better, and is about 20 mins per region.
> So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session. This is literally in the "blood test" expenses range.
We get around that number out of our scanners doing real scans and our costs are a lot more than that.
I don’t see staffing mentioned? A good tech will improve throughout, and you need more than one. A good operation will have several per scanner. They reduce the ever present danger and keep the operation running smoothly. I’m biased, I’m a tech.
Another thing missing - liability. I work in a country that isn’t quite as full of lawsuits as the US. Whole body scans are a glorious way of collecting liability. Poor quality images of everything in ‘well’ patients. As a rule in imaging, ask a good question get a good answer. When you’re searching the whole patient for something’s it’s easy to miss something.
> How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building?
Mass production happened. And this time it has taken the industry completely by surprise.
The radiologist needs to be onsite. We give drugs. They inject things, they biopsy, they are doing stuff.
Yes, lots of stuff can be done remotely and AI assisted. Assuming they can all be replaced assumes a role that the radiologist had a long time ago, or maybe never had.
There are a lot of efficiencies that can be made, and radiology needs all the help it can get, but it isn’t a ludicrously inefficient or stuck in the past.
> I don’t see staffing mentioned? A good tech will improve throughout, and you need more than one. A good operation will have several per scanner. They reduce the ever present danger and keep the operation running smoothly. I’m biased, I’m a tech.
That's why I put the cost of the scan at $1k, to make room for a profit margin and the staffing cost (which will be more than equipment).
Liability is an issue, but not an insurmountable one. If you get poor-quality images, you can just retake them. So biasing radiologists towards that can be a workable solution. There is also a lawsuit in the US going on against one of the full-body scan companies that missed a cancer, so we'll see how it turns out.
> The radiologist needs to be onsite. We give drugs. They inject things, they biopsy, they are doing stuff.
For clinical MRI. Not the diagnostic screening ones, they are done without any contrast.
> There are a lot of efficiencies that can be made, and radiology needs all the help it can get, but it isn’t a ludicrously inefficient or stuck in the past.
Radiology is fine, the AI will help them to do quick screening and point out possible pathologies.
I think you're missing the point. The psychological cost of a conditional-positive result is nonzero, and can be very significant (I speak from a little bit of experience here). But far more importantly: the physiological cost of invasive followups when you eventually trip the threshold of "time to go explore with a scalpel" is very high, and the missing evidence this story is about is whether you can get to that threshold with an MRI.
Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
> Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
Again, _all_ you need to do is to make a follow-up scan in 1-3 months to see if there are any changes. It's a preventative tool, so unless you have other indications, it's almost always safe to wait for a bit.
And yes, it requires educating patients that sometimes just waiting and doing a follow-up scan is right. And yes, I also have a personal experience with that (I had an "idiopathic lymphadenopathy", aka "we don't know WTF is going on").
It's a good thought experiment, but what you really need here is a randomized controlled study to see if your new plan results in better outcomes, before you roll it out to the whole world.
* Doctors and medical researchers keep saying that routine MRIs for non-symptomatic or low-risk patients is a bad idea, because the outcomes are worse than not scanning.
* There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy.
* Nevertheless, here we are, nerds arguing we know better than all these people.
And I don't buy that. EXACTLY this was also said about prostate cancer screening. Word-for-word. "Overdiagnosing", "people are better off not knowing", "psychological burdens", "invasive procedures", etc.
Now we have multiple longitudinal studies of people receiving aggressive screening and the usual standard of care. The aggressive screening group, unsurprisingly, has better outcomes with less mortality.
> * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy.
Yeah. I guess it's time to stop using fire alarms. People are better off not knowing if a building is on fire, and frequent false alarms have a negative effect on psychological well-being.
Just look at the risk of burning to death. Alarms make no sense at all!
> * Nevertheless, here we are, nerds arguing we know better than all these people.
Yes. Absolutely. And I actually have read (I think) all the studies, and came thoroughly unimpressed. They're utterly sloppy with poor statistical analyses.
It's absolutely an indictment of the medical industry that has become so crusty that it can't be bothered to integrate new diagnostic modality. That is the _only_ way to detect multiple lethal cancers while they are still curable.
You're not engaging with the logic. Stipulate that it is the only way to detect multiple lethal cancers. If you end up harming more people than you help, the intervention is bad. Right now, you're only looking at one half of the balance sheet.
> Stipulate that it is the only way to detect multiple lethal cancers.
This is trivially true.
> If you end up harming more people than you help, the intervention is bad.
The only pathway through which diagnostic MRIs can feasibly harm people is aggressive follow-up of uncertain findings. And this is almost completely solved by just doing another scan several weeks/months in the future. With corresponding patient education.
This is literally all what was needed in the case of prostate cancer screening: less aggressive biopsies and bias towards observation rather than action. Yet it took _two_ _decades_ to arrive at this point. And some doctors _still_ refuse to order screening tests out of this misplaced idea of "not knowing is better".
And this is not the only time when "geeks knew better". For example, checklists for surgeries are a no-brainer to anyone with an aviation background. Yet they became standard only two decades ago ( https://pmc.ncbi.nlm.nih.gov/articles/PMC6032919/ )! Over rather strong objections from doctors.
The people arguing against routine MRI scans are the checklist people!
But, look: if you think routine prostate screening is a good idea, I don't have a counterargument. You're right: there's already an emerging discipline of watchful waiting with prostate pathologies.
The argument being made here is about full body MRI scans: doing a dragnet sweep looking for neoplasms anywhere and everywhere. Not the same thing! Similarly: my belief that the EBM people are right about full-body scans doesn't mean I oppose colon cancer screening!
> The argument being made here is about full body MRI scans: doing a dragnet sweep looking for neoplasms anywhere and everywhere. Not the same thing!
It's exactly the same thing, but on a larger scale. Yes, it will likely require at least some adjustment to the standards of care and development of more stringent criteria for follow-up procedures. But we're already talking about fine-tuning, rather than something fundamental.
Here's a study from one of the providers:
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer. Of these cancers, 68% didn't have targeted screening tests and 64% were localized when detected. The company says it finds possibly life-threatening conditions in 1 in 20 people.
So we're talking about the real-world 4% rate for biopsies, with about 50% false positive rate. This is not that far removed from the current clinical 30% false positive rate. And this is far from the apocalyptic scenarios of multiple biopsies for every patient.
> To date, no study has been performed that rigorously investigates the impact on disease-specific survival following whole body MRI in asymptomatic patients without specific risk factors, and no study has been performed to confirm that a ‘negative’ whole body MRI excludes significant disease 5 or more years’ later.
The only real remaining argument is cost effectiveness of MRI, especially for government-based healthcare. It is a valid argument, but it's beside the point for people who are self-paying. And it's also missing the implications of economy of scale.
So I'm pretty sure in this particular case the geeks indeed know more than doctors.
> Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans?
Doctors have already thought of this. Several issues with it:
* Monitoring still causes anxiety and mental health issues which come with real effects on patient's quality of life. It's not "harmless".
* Unclear when to monitor and when to treat. It's also really hard to get enough data to characterize these early unspecific findings enough to get confidence on what to do.
* Monitoring via MRI might be just as useful as monitoring via symptoms or any other "passive" methods that do not require a previous scan.
There are two points in MRIs that limit or (better) regulate their use:
* financial cost vs level of care. A full body MRI costs a huge sum but it is the most detailed non-invasive diagnosis we have for any disease that can lead to earlier therapy. Used as a screening method, does it worth to save one patient in tens/hundreds tests performed? You answer, but public health authorities, health insurances and medical societies are negative.
* MRI shows some minor findings that would never cause symptoms and better not be known to the patient due to the stress they bring and cost of ongoing follow up (eg in the brain small meningiomas or angiomas). This might bring more harm than good and limit their net value.
For some reason, I always found the arguments for "it's better to not know" for these tests to be strange and slightly infantilizing. But of course this must not be the end of it, and there might be some more well thought out arguments from bioethicists that go beyond "the patient can't handle the truth". Because this argument seems like it's doing a lot of heavy lifting without much evidence.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer
So that would be 1.71% of people getting a full body MRI catching cancer early.
That seems like an astoundingly good return to me. What does late cancer treatment and lost lives cost? Many times these MRI’s.
If everyone did this, would there be any significant number of late stage cancer discoveries anymore?
Obviously, reducing the cost of false positives is important. But if 1.7% of us have cancer - wow. My guess is that percentage can be tuned up and down by demographics. So maybe there is still an argument against everyone doing it.
Many of those cancers are not harmful or would be killed ok their own. And the cost of diagnosis on the patient is not free either. It causes lots of anxiety and stress which also cause large negative health effects too. Over diagnosis is real and also bad. Medical stuff is just really hard
There’s a major difference between having insurance cover something (socialized cost, immediately drives up provider fees for bizarre reasons) and letting the market allow people to buy it themselves (individual cost, the market drives the cost down fast and hard). Notice the pattern with LASIK and GLP1 where lack of insurance coverage has counterintuitively made it cheaper and more accessible.
Let everyone who wants to pay get their scans! But don’t make me pay for you
Can one solution be always doing two scans, N months apart, before drawing any conclusions (excluding things that can be reliably detected from a single scan)? Initial scan could affect N (if you find something potentially aggressive, you can schedule the second scan sooner). And then do a follow up every M years.
That should exclude benign or very slowing growing things
Extremely anecdotal: my dad’s lung cancer was found incidentally - shoulder pain → shoulder MRI → radiologist noticed lung nodules. The shoulder pain was unrelated, but the scan itself was clinically indicated and there were prior scans to compare against, which made it immediately suspicious and triggered follow-up imaging.
He was also in a higher-risk group (age + history), which in hindsight probably made the incidental finding meaningful rather than noise.
So cases like his make me think less “scan everyone periodically” and more “imaging can be very valuable once risk is non-trivial or there’s a baseline to compare to”. For the general population you’d mostly generate false positives, but for higher-risk groups (older, smokers, prior findings) it seems much more defensible.
Wrt the issue at hand: yes the cancer was found as an incidental finding on a scan performed for another indication (shoulder pain) -> the question remains whether your father benefitted from finding the cancer. This is seldomly the case.
Anecdotally, everything is possible but on a population scale, actual survival benefit is rare - whereas suffering from the downsides is not - even if only counting unnecessary healthcare cost and time wasted.
In my dad’s case it very likely did - it was lung cancer and still pre-symptomatic, but had already started to metastasize, so a later discovery would probably have meant a much worse prognosis category.
I agree anecdotes don’t generalize and broad population screening sounds like a bad tradeoff.
What I’m wondering about instead is risk-stratified situations: once someone already has elevated risk or prior lung disease and you’re imaging them periodically for legitimate reasons, incidental findings may carry much more signal than noise.
For example, people with prior tuberculosis often get periodic chest X-rays, not to screen the general population, but because their baseline risk is different. My dad had prior lung disease and existing imaging to compare against, which probably made the finding actionable rather than just another false positive.
So not “scan everyone”, more “the usefulness of incidental findings rises quickly once pre-test probability isn’t tiny”.
Just to point out, cancer isn't the only reason to get these. Aneurisms, hemachromatosis, etc can all be serious. I know someone who got scanned for $500 and they caught hemachromatosis via iron deposits in the liver. Much better than eventual chirrosis and liver failure.
If you get the MRI you are performing simultaneous blind tests for a thousand rare, unsuspected conditions. The blood test only tests for one of them, and eats 10ml of blood. There isn't enough blood in your body for all those tests.
We should arguably be, in an ideal healthcare system, getting annual MRIs with the other typical tests in a physical, and feeding that data into an AI, and have the AI issue recommendations for informed hazard & secondary testing/biopsy priorities. Tomographic analysis and differential diagnosis is exactly the sort of multidimensional pattern recognition task an AI is great at compared to a human doctor, if you can provide the training data.
Normalizing an annual MRI is the biomedical equivalent to survey astronomy and opening up those gargantuan datasets - you expect lots of simultaneous serendipitous discoveries in unrelated areas without securing an organizational mandate to fund a dedicated research effort into each one of them. The worst the process is ever going to be diagnostically is right now before we're collecting any data in a concerted fashion - every bit of training improves it.
A blood test doesn't scan for other issues. A genetic test and iron study is going to run a few hundred dollars. Add in the cumulative cost for the other conditions checked for, like aneurism, and a $500 MRI isn't that bad.
MRI does not diagnose hemachromatosis. It detects iron deposits (could be due to other harmful issues). To my knowledge it would not produce a false positive. Hemachromatosis is the most common genetic issue in white people, so pretty common (I'm too lazy to look up stats).
I much prefer tests with low false positive rates.
I recently had such a cancer-related test. A cousin had a BRCA2 mutation and I was concerned I could have it also. Insurance would not pay for the testing, but one can get a panel of such genetic tests for just $250 now, so I went ahead. And it was negative. This is reassuring not just to me, but also to my children, and (somewhat) my sibling (the relevant parent is no longer alive).
Had this test been positive, the chance of pancreatic cancer would have gone way up, so frequent scans (I think annual MRI and ultrasound?) would have been justified.
People often contain features in their body that look abnormal on an MRI but might not actually be issues. The issue is that an MRI doesn’t give enough information to know otherwise. This is why they are typically not used in a routine exam by mainstream medicine.
It’s like running ‘ls -la’ on a directory to determine if there are any issues with a piece of software. It could show things that are really bad. It could show things that look weird. But it won’t conclusively debug the code.
I don't see the point of testing constantly. It's just creating stress and probably most of the time, the tumor might be benign or it might be small and go away on its own.
And anyway, you have to die of something so for me cancer would just be a sign that time's up.
> The tests range from several hundred to several thousand dollars, depending on which sections of the body are scanned, and are not covered by insurance.
Even ignoring the overdiagnosing problem (I don't understand how they can determine from MRI when a cancer is a cancer; there are also benign growth and often when they are a certain size, people notice them, but how would MRI help here? Too small areas could be classified as malign; any further procedures can be dangerous - see that Dawson Creek actor recently, the cost of clinical intervention did not help), I think that medicine is increasingly becoming a "only affordable for those who have money". You can see this with regards to gene therapy too - if we ignore the success ratio, many of these therapies are impossible to acquire for Average Joe. Granted, the prices will go down for various reasons (we saw this with Moore's law and many other inventions too), but at the end of the day I feel we are stepping closer and closer to a very unfair society model - more and more superrich, but prices also go up immensely for average people. That model is not sustainable; people will be angry since this is not fair.
Frankly, this sounds like some people aren't so comfortable with the sheer cost of the machine than their absolute utility. CT and MRI scan machines are something that said to cost like $1m/yr/unit that's ~$500 uninsured/$100 insured per run in Japan that China don't publish data on numbers or distributions of. That says "military grade expensive" written all over.
Doctors absolutely hate the idea of people being checked for diseases. Every time someone comes out with a plan to detect cancer or prevent HIV, they start screeching.
“But what if the person would have died anyway without noticing they had cancer? Think of the shareholders. They would have paid for treatment for nothing”
“ One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.”
This has been my experience. And I’ve had oncologists echo exactly this. In the words of one: MRIs find too much.
The CT and the PET/CT are the gold standards for finding cancer, finding recurrences, and staging cancer. The trouble is the radiation dose.
MRI provides very inconclusive results. You’ll see something but it’ll be unclear what it is. And often what you see is not even visible on a CT. Or it’s visible on a PET/CT and is showing metabolic activity indicating its cancer.
MRIs are great for certain things like herniated disks in your back. They suck at cancer.
It's not that MRIs suck at cancer. They provide fantastic structural and functional data.
The problem is the specificity of the results and the prior.
A full body MRI by definition will provide detailed views of areas where the pretest probability for cancer is negligible. That means even a specific test would result in a high risk of false positives.
As a counter point, MRS means that you can now MRI someone's prostate and do NMR on lesions you find.
Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as do a analysis that would otherwise require a biopsy. With the raised prior you can be quite sure suspicious lesions are cancerous.
Similarly for CNS tumours. Where fine detail. Subtle diffusion defects can mark csncers you couldn't even see if you cut the person open.
No sensible doctor would give you a whole body CT unless there was a very good reason. That very good reason is probably "we already think you have disseminated cancer". That pushes the prior up.
And less so for a PET/CT. Lets flood you with x-rays and add some beta radiation and gamma to boot!
The danger of an unnecessary CT/PET is causing cancer, the danger of an unnecessary MRI chasing non existent cancer.
> Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as ...
Not a doctor - but maybe start with some quick & cheap tests of their blood & urine, polite questions about their sexual partners, and possibly an ultrasound peek at things?
At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
Source: Bitter personal experience.
> At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
Maybe it's a regional thing, but that hasn't been my experience. I've had one MRI and one CT scan in the 25+ years that I've been a full-time employed adult with insurance.
I'd have been happy to sign up for more so I could have proactive health information and the raw data to use for hobby projects.
> The danger of an unnecessary CT/PET is causing cancer
You'd have to be massively overexposed to CT or PET scanning to cause cancer, like in the region of spending months being scanned continuously with it at full beam current.
Even if you don't agree with linear no threshold models for cancers induced by radiation (I don't think LNT is accurate).
It comes down to the scan and the age.
3 scans for a 1 year old? Strongly associated with cancers later in life. 5 scans of a 50 year old? Less so.
The 1 year old has an 80 year run way to develop cancer, along with cells already set in a state of rapid division, and a less developed immune system.
But the association is quite strong.
https://www.sciencedirect.com/science/article/pii/S0720048X2...
> 3 scans for a 1 year old? Strongly associated with cancers later in life. 5 scans of a 50 year old? Less so.
Someone being born with no legs is strongly associated with them using a wheelchair in later life.
Why are you giving a one-year-old three CT scans? For shits and giggles? Or because you think they might have cancer?
> I don't think LNT is accurate
There's excellent reason to think LNT is accurate: at low doses, almost every cell is exposed to at most one radiation event. The dose affects how many cells experience a (single) event, but does not affect the level of damage to those exposed cells. Linearity naturally falls out of this.
To abandon linearity you have to imagine some sort of signalling system (not observed) that kicks in at just the dose we're talking about (not lower, not higher) to allow exposure to one cell to affect other cells.
There's also no good evidence that LNT is wrong. The typical things that are pointed to by anti-LNT cranks are cherrypicked, often involving interim results from studies the full results from which do support LNT, which is evidence it was statistical noise.
I think the bigger point you are making is that the 50 year old is also more likely to have developed cancer.
Maybe a full body MRI once a decade is fine until your 30s, then once every 5 years until 50, then once ever 2 years beyond 50.
The test should scale with the probability of cancer.
They were not talking about MRI, there is a significant difference (purported).
They were not talking about MRI, there is a significant difference.
> You'd have to be massively overexposed to CT or PET scanning to cause cancer
The mean effective dose for all patients from a single PET/CT scan was 20.6 mSv. For males aged 40 y, a single PET/CT scan is associated with a LAR of cancer incidence of 0.169%. This risk increased to 0.85% if an annual surveillance protocol for 5 y was performed. For female patients aged 40 y, the LAR of cancer mortality increased from 0.126 to 0.63% if an annual surveillance protocol for 5 y was performed.
https://pubmed.ncbi.nlm.nih.gov/36856709/
> 0.126 to 0.63%
So, a just-about-measurable increase, if you pick and choose your values carefully?
You are not going to die from cancer caused by getting a PET scan. This will not happen.
You're going to die of heart disease or as a not-too-distant second in a car accident.
That data is for one scan, ever.
Continuous scanning for months would give a dose many orders of magnitude higher.
Approx. 5% of all cancers in US are caused by CTs
[citation needed]
5% seems a bit high, but we are nearly there.
https://www.facs.org/for-medical-professionals/news-publicat...
I think they're reading too much into it.
How are they determining "this cancer was caused by the CT scan" versus "this cancer was caused by the cancer we were originally looking for that was there all along"?
Radiation doesn’t label the cancers it causes.
Other than comparing population groups, what method do we have?
Well, you could work backwards and look at your assumptions.
Why is "We think this person has cancer so we gave them a CT scan and look! Now they've got cancer! It must be because of the CT scan!" the conclusion to jump to?
Please just read this article - https://jamanetwork.com/journals/jamainternalmedicine/fullar... It's funny that you instantly assumed that authors are stupid and did not think about this obvious pitfall. It's extra funny that you also accuse them of jumping to conclusion without actually reading the article.
I've read it. It's so comically unscientific.
What's unscientific in that?
> MRIs are great for certain things like herniated disks in your back.
I have had a lot of experience with MRIs on both myself (back and knee [1]) and my dogs with herniated discs. The doctors always make it sound like MRIs are great to confirm what's suspected because of other symptoms like pain, but a point in time MRI alone is not that valuable. Everyone's bodies (including animals!) are surprisingly different inside making normal be somewhat unique. I think what would be interesting is if scanning technology like MRIs could be made so inexpensive and easy that everyone had one done 4x/year. That way it's the differential being checked and I'm guessing it would be way more valuable. Normalization such as this could also lower anxiety around findings.
[1] Even when I tore my ACL the MRI came back only as probable.
Do you know which MRI you used? Not all are equal. Most MRI are 1.5T powered, and you can’t get fine details until you hit 3T. And there are differences even in the 3T power range. There are higher powered MRI which are mostly only used in research, whilst it is a bit scary thinking about the sheer power of them but a 7T machine doing a full scan of you, would be guaranteed nearly to find anything wrong with you.
When I last looked the full body scans for sale seemed to used 1.5T setup, which seems like a waste. The 3T advanced scans looks much more detailed, but it just depends on where you live - I couldn’t find any around.
My knee and back was years ago, so probably the 1.5T. No idea on my dogs who have had the more recent MRIs. Their scans are incredibly detailed though, so maybe the 3T?
Spot on. And dealing with false positives sucks.
One caveat is that regular PET isn't so good in the brain - there is so much metabolic activity that everything glows. So I get an MRI Brain to go with my regular full body PET/CT (cancer 5 years ago with recurrence 18 months later, currently NED).
I had a CT scan last year for some stomach issues they wanted to look at.
Doctor warned me up front that the odds the images find something that looks weird is high but not to panic because of how many false positives there are when looking inside someone’s body.
While I am happy to report they didn’t find anything serious, I do take slight offense to the following at the top of my results:
Last name, First name: Unremarkable
(Kidding of course but still got a chuckle out of me)
> I do take slight offense to the following at the top of my results:
No offense for me, just confusion. One of the status reports started as follows:
> OptionOfT is a very pleasant 36-year-old gentleman 6 weeks status post left anterior total hip arthroplasty done by Dr. _ on _.
I asked my wife whether I was particularly friendly (I sometimes fail to adjust my demeanor in certain situations).
She said: nah, they write that for everybody.
The bar is really low for patient behavior. Tbh I find anyone not screaming at me to be pleasant in comparison.
Some RIS systems make semi form reports with ‘Dear <referrer> thank you for sending <patient> to see us for their <type of imaging> etc etc.
Then you can just tab from field to field when doing the report.
I had a nurse chart “patient ‘feels like a million bucks’” while I was getting an immunotherapy infusion.
She said “It’s just not often I hear that here.”
2.5 years in of regular PET scans. At this point, I’m almost humored by what gets flagged as suspicious by the radiologist - usually mosquito bites and stomach bugs (kids in daycare means I’m almost always sick). I have a scan Monday and two weeks ago had a re-excision so there’s a two inch gash healing on my back. This week I got three vaccines. And then tonight my toddler bit me hard enough to draw blood. I had asked the oncologist if it made sense to delay the scan because of the re-excision and he said not to worry because he’d know why there’s inflammation in that area. I’m thinking the bite and the shots will probably get flagged too. I just hope I don’t forget any other maladies or mishaps that might get flagged that I can’t explain.
How often are they finding actual positive hits on the PET? If its so unreliably with regards to false positives why do you continue to have PET scans done?
PET Scans feature areas with blood flow so tumors show up as hot spots for follow up. People who are maybe only feeling off or had one confirmed tumor can have a lot of small tumors spread across their body which will show up clearly on a PET scan.
When my brother was at the end of his run fighting cancer he felt a bit under the weather and managed to catch covid so everyone figured he was feeling bad due to that. The PET scan showed he had thousands of small masses converging into the large mass that eventually killed him by cutting off blood flow to his kidneys. His cancer was an aggressive blood cancer that had stood up to conventional and Trial Chemo drugs. There was no way to treat this but other cancers that are less aggressive can be treated at this point and would be treated differently than a single mass.
In a nutshell it’s that level of visibility that makes PET scans worth it.
PET scans are not really unreliable, they’re just very sensitive and lots of anomalies ranging from benign cysts to malignant tumors show up on them. It’s not always possible to differentiate them without other measures like biopsies, so that’s where the false positives come in.
Getting regular scans to track cancer progression is a different matter altogether, since most of the blips can be eliminated over time and there’s a history to compare against.
Anecdotal evidence to confirm: I had two false alarms from an unrelated MRI scan, and beside wasting a lot of time on diagnosing them - it was also extremely stressful.
My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment,
These treatments are wonderful and it is great that they exist. But many people fail to understand the difference in terms of pretest probability, etc.
I can absolutely see the heavy psychological impact pending biopsy results may have. People are quick to discount these issues when you raise them as a concern, but only if they never went through this stress themselves
I have multiple scans a year. "Scanxiety" is real.
> Scanxiety
Cute written word - even though two words pronounced completely differently at join (an versus añ).
Which do you pronounce correctly the scan or the anxiety? [scan]xiety or [sk]anxiety
The former. It doesn't quite roll off the tongue, but with my (Australian) accent the difference is minor.
Kiwi here - I'll use the word with my friends in future because a label does help.
As a non-native English speaker, pronouncing it scan-xiety (sken-ZAHyetee) feels correct.
I do once a year and have skipped 2 because of that. I've since resumed but for a while I convinced myself I'd rather not know.
Multiple PETs?
Yes, with MRI brain too. I was on 4/year, but that number is reducing as time goes on without recurrence.
Sorry, I missed a key detail. What you are describing isn’t the ‘whole body mri’ I’m referencing by to.
People in high risk situations like multiple myeloma, or various metastic diseases, or system conditions are a whole different category and there is clear benefit to screening them.
It sounds like you have had a tough time.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
My mum gets scanned a little more frequently than that, following treatment for an inoperable tumour in her lung around five years ago. During treatment she was getting scanned every three months or so, and it was remarkable watching this thing go from the size of a tangerine, to actually expanding a bit and looking "fuzzy" once the drugs kicked in, to being the size of a plum, then the size of a grape attached with a little thin thread of tissue, to being a thing the size of a pea. Now there's a tiny ripple of scar tissue that no-one wants to investigate further, because if it's not doing anything let's not poke at it.
There is a roughly pea-sized "thing" on her adrenal gland that was a bit worrying because anything like that is going to get intimately involved with your lymphatic system and then it's going to metastasise like hell. But it neither got bigger nor smaller in the nearly six years since the first scan, so it can't be that important.
This is one of the great things about the NHS, especially here in Scotland where we have (possibly as a result of the weirdly high levels of cancer) some of the best oncology services in the world.
If we'd lived in the US, the insurance companies would have taken one look at an 83-year-old about to become a grandmother and sent her home with a bottle of morphine to die. As it is, she's doing very well and got to see both her grandchildren start school.
> in Scotland where we have (possibly as a result of the weirdly high levels of cancer)
Interesting, I had no idea and just looked this up[0]:
> Scotland had the highest overall incidence (446 for men and 379 for women per 100 000), and Wales had the second highest rate (450 and 366 per 100 000), compared with 394 and 338 per 100 000 in England and 394 and 345 per 100 000 in Northern Ireland.
This would make Scotland rank 3rd in the table on https://en.wikipedia.org/wiki/List_of_countries_by_cancer_ra... .
PS: Glad to hear your mom is doing well!
[0]: https://pmc.ncbi.nlm.nih.gov/articles/PMC1939786/
> PS: Glad to hear your mom is doing well!
Thanks, she had little to no side effects from the experimental immunotherapy drug. She'd said at the outset she didn't want to be a "chemo zombie" having been through all that about 20 years ago (she's had four different cancers throughout my lifetime, treatment getting better every time).
It's fucking expensive, but immunotherapy is really a miracle cancer treatment. We're not quite at "Oh you've just got a wee bit of cancer, we can give you something for that if you see the pharmacist on your way out" but we're not far off.
“MRIs…suck at cancer”
Wrong? I understand MRIs are the standard for certain types of cancer like brain and spinal tumors.
With respect to whole body MRI they can be less effective because it’s not optimized, accuracy can be traded for area.
But as a general statement MRIs do not suck at cancer.
MRIs are good if you know what you’re looking for, and usually with contrast, which in a situation like cancer where you need to do them often can result in allergic reactions.
In a full body situation, they are looking for mets, and the uptake of radioactive sugar by the tumors will let a PET scan find them.
That’s completely and 100% false. It’s much easier to characterize things on MRI and MRI is indeed phenomenal for cancer! The problem is with screening, not actual staging or follow-up, and whole-body screening in ct and pet/ct is even worse than MRI screening even if you ignore radiation.
>One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
That can also be reframed as 1.71% of asymptomatic people having cancer, which is a really good argument for better screening.
The argument for better screening would require that finding those asymptomatic cancers actually improves survival rates. There are several reasonable scenarios where early screening doesn't improve it:
* The cancer is aggressive and resistant to treatment. Chemo/radiation only pause the growth for a bit, but ultimately the cancer keeps growing and the total survival time is the same (only that the patient spent more time knowing they had cancer).
* The cancer is susceptible enough to treatment that it's still curable when it becomes symptomatic and found through other means.
* The cancer is slow enough that the patient dies from other causes before.
Early screening brings benefits only when the cancer ends up causing issues and responds differently to treatment between the "early screening detection" time and the "normal detection" time.
It's impossible to know beforehand which of the scenarios have more weight, specially because we have very little data on what happens way before cancer is detected via the usual methods. We need better studies on this, and for now the evidence doesn't really point out to these large, indiscriminate screenings being actually helpful.
That’s not the correct framing - your assertion first lacks evidence about why we should screen better. In fact, we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Further, the denominator is asymptomatic people who were able to get MRI’s they didn’t need. That doesn’t tell us anything about the normal world.
> we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Even assuming your statement is true, if what is detected is small enough for that there's no reason "treatment" can't just be monitoring it's size with follow-up scans.
> Even assuming your statement is true,
It is true. You need only trouble yourself to search. Here's a recent paper, for example: https://jamanetwork.com/journals/jamainternalmedicine/articl...
> if what is detected is small enough for that there's no reason "treatment" can't just be monitoring it's size with follow-up scans.
This is false—it is exactly what the article is trying to convey. There is a risk to any test, and one of the major risks for imaging is getting treatment for things that would never cause symptoms or require intervention.
If the cancer is vizible in MRI or CT scans, the immune system already failed to "resolve" it and will not do so in the future, at least not without external help.
> If the cancer is vizible in MRI or CT scans, the immune system already failed to "resolve" it and will not do so in the future, at least not without external help.
This is false. A simple google search for spontaneous remission (or honestly anything similar) would show/have shown you this.
I wonder how biased the group is though, is the sample truly representative of the general population or is it a group of people who are already undergoing screen for some other health-related reason?
Not because of an MRI, but this happened to me:
N=1, but that biopsy should not have happened.I don’t understand how you’re concluding that the biopsy shouldn’t have happened from that anecdote? Just because a test result is negative doesn’t mean that it shouldn’t have happened. That’s not how practicing medicine works.
Hence the N=1 I started the statement with. If we had a thousand similar situations and it turned out that in, say, 1% of cases there was a lung tumor, then we could debate whether it's worth putting 990 people through a biopsy they don't need so 10 can find out they have a tumor. Maybe that gives us the opportunity to discuss waiting a month and taking another chest x-ray (which has its own negatives) vs. doing an immediate biopsy.
But we don't have 1000 similar cases. As I said, we have 1: mine. And it turned out negative. So 1 person was put through a biopsy they didn't need, and 0 people found out they have a tumor.
Hopefully that makes my point clearer.
>MRIs are great for certain things like herniated disks in your back. They suck at cancer.
MRIs are fine for certain kinds of cancer like liver cancer.
But saying MRIs "suck at cancer" feels off. They're actually first-line or gold standard for certain cancers
I feel that label is actually deserved. Yes, some cancer types are easier to detect with MRI, in particular inside of a body, but at the same time MRI in and by itself isn't great at predicting all cancer types. How could it help with regards to leukemia, for instance? What exactly could MRI detect here better than other diagnostic tools? One has to keep in mind that diagnosis also takes time - plus the cost; and the overdiagnosis problem which means that some cancer that are not really relevant, are hyped up by MRI to be the end of the world for a patient. So there is a trade-off.
IMO MRI needs to become cheaper; and more reliable too.
hmm that is still around 1.5% of ppl having cancer. not trivial. Even more if you include false negatives.
I mean, i think you need to look more into it than that.
If you make a test that always returns true, it would also meet that criteria.
Basically half of all men have some early form of prostate cancer. Now that does not show up very well on an MRI, but there are quite a few diagnosis like that that are not necessary life saving.
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And yes getting frequent full body MRIs is still overwhelming the right thing for the patient.
No? The point of the article, and of the preceding comments, echoing a pretty common tenet of evidence-based medicine, is that frequent full-body MRIs are a bad idea for the patient.
This guy has never heard the term 'scanxiety'. Go ask what it means on a cancer forum. The real OG's are the VHL folks. Bet we have a few here on this thread. Respect.
I have, it's the fault of how medicine is practiced to reduce cost. It's completely avoidable, you can just not tell people their scan results if they have no symptoms and the detection is less than 95% likely to be cancer. This is strictly better than the status quo because the only difference is some people who almost certainly have cancer learn that they have cancer and nothing else changes
Again, you're assuming the only downside of a routine scan is anxiety. No, the real downside is that you'll trigger needless invasive procedures.
How can you trigger an invasive procedure if nobody learns the result of the scan?
Obviously, the doctor does. Nobody was ever claiming that the problem with full-body scans was that patients were demanding biopsies!
Right, the problem in your model is that the doctors do! I am pointing out that this is a problem with the doctors, not the scan.
Scans are a tool, doctors are not allowed to use them rationally because it would be too expensive, so they don't use them. With an ideal doctor, patient outcomes would be better with a scan than without one, but my claim is that doctors are not ideal.
No doctor would order a full body MRI just to throw out the result in 99% of cases, because *it's too costly*
Doctors are not ordering biopsies to salvage the value of a scan they just ordered.
I agree, but they are failing to order scans when the probability of finding anything worth biopsying is low because of cost.
This is so obvious it's crazy, our entire world view is misshaped around saving money.
When you walk into a doctor's office, why do they take your blood pressure and temperature? Why do they look at the back of your throat and listen to you breath?
These are all diagnostic procedures with extremely high false positive rates. The reason doctors do these but do not do MRIs is because MRIs are expensive.
If MRIs were free you would get one automatically every time you go to the doctor.
No, you still wouldn't, because doctors are neither free nor perfectly rational.
The probability of finding something worth a biopsy is not low, it is high compared to the probability of the patient requiring intervention.
Yes that is my point. It's about cost
That's not what they said.
> you can just not tell people their scan results if they have no symptoms
This article is about services like Prenuvo, where the entire point of the service is to get the results of elective scan not related to any symptoms.
Here in NZ an Australia, the college of radiologists disagree and say ‘don’t do it’ for screening the worried well.
https://www.ranzcr.com/college/document-library/2024-positio...
Seems like their main concern is "substantial downstream healthcare costs"
Yes, and needless biopsy can be a big deal.
It’s a great document, I’m an MR tech and we now have something to lean on when we say no to these scans. We can then scan people with problems rather than people with too much money.
Great document? I just read the entire thing, it contains no evidence or justification for their claims.
> We can then scan people with problems rather than people with too much money.
Right, this is what it's really about. MRIs are a scare resource and providers need to manage cost. Fortunately I can afford to pay out of pocket, but I'm just annoyed that doctors are so irrational about this
To be clear, it's up to a doctor whether or not to do a "needless biopsy". That has nothing to do with a scan.
… they do it based on the scan result.
Avoiding a biopsy that wasn’t needed is a good thing.
You're imagining that the doctor is required to act irrationally or against the patient's interest. I understand that they do act this way, but I'm pointing out that they don't have to!
You walk into a doctor's office and meet for the first time.
Case 1. You have 3 full body MRIs taken 6 months apart in hand and give them to your doctor. Nobody has opened or looked at the scans yet.
Case 2. You do not have a scan yet
You are claiming case 1 will lead to worse outcomes in expectation. I claim that's impossible because the doctor can simply do the following: Without opening the scans, email them to the world's best radiologist. Tell that radiologist "only reply if it is nearly certain the patient has an operable cancer with the information available"
Now there are 4 possibilities.
Case 1 without cancer: nothing happens
Case 2 without cancer: nothing happens
Case 1 with cancer: you maybe survive
Case 2 with cancer: you die
The only reasonable objection to this is "that's expensive"
A whole body MRI is low resolution and thick slices, they are crap.
Instead you could get thin slices at high resolution of a body site that has issues or is suspected to have them. Do that instead.
Whole body MR is 5-8mm thick slices at low in-plane resolution. A whole body scan has about 512 pixels over a 50-60cm field of view. Usually it’s even less pixels than this.
Something like a knee, or brain is 2-3mm slices, and high in-plane resolution. A knee is 512 or even 720 pixels over 14cm. It’s vastly better. The difference is stark.
A liver scan or other abdominal organ is lower resolution than a joint or brain, but unlike whole body MR is scanned in multiple planes with multiple image weighting (t1 in/out/fat sat, diffusion, t2, t2fs, gadolinium contrast). A liver scan has thin slices.
Whole body scans generally do two coronal images (stir and t1) then call it quits.
Yes the machines should definitely get better, but I recommend you do get it if the cost it truly zero. Based on the data in the article it is still worth it despite the low resolution!
Sorry, I edited my above comment to remove references to myself.
For clarity, I’m an MR tech and I can get scans of myself if I want to.
I generally don’t scan myself as it gets messy fast. If I had concerns and for some reason couldn’t get a proper imaging referral, I’d get a scan with small, good coils with high element counts (not body coils like whole body imaging uses) and scan individuals body regions.
It is not only money, machines and doctors are also a limited resource.
The other bit is that no one follows your protocol, everyone looks at the scans, finds reasons to worry. Then you have the choice between unnecessary biopsies and psychological stress.
I agree, and I think rationing is the correct thing to do. I just don't like being gaslit by doctors (or would prefer doctors who know better).
And I agree most doctors won't do this, but again I blame the doctors and their training
I kinda agree with you and I understand your point but I also think there is a social-ethical reality that if a doctor finds something they must treat it. The two options are 1. doing nothing, or 2. reducing cancer risk and you get unnecessary biopsies.
You're thinking of this as there being an objective positive utility for not dying of cancer and a objective negative utility for biopsies, and there being an objective optimal "rational" tradeoff that the best radiologist can optimize for to get their "nearly certain" detection threshold.
But frankly - the tradeoff for the value of a human life is perhaps the most uncertain thing one could choose. It lies in the eyes of the patient if the worry and time associated with a false detection is worth their reduced chance of death. The ethical uncertainty expressed in the OP - are these unnecessary biopsies worth it - is warranted.
You a-priori do not know if you have cancer. The case 1 branches are:
Case 1 without cancer: you're a guy that knows more than doctors because you're the "I have 3 scans on hand guy", so as soon as you open the scans and the doctor says there's a mass, you will say 'OK what can we do???' And then you had a worthless biopsy.
Case 1 with cancer: you saved the 1 week it would take to schedule the new scan and get results and you're basically in the same situation except one week earlier.
That's not how it works. Without the history of scans spaced out in time, they would typically need a biopsy. Multiple scans over time shows change and growth and improves the likelihood of an accurate triage
And for the first part that doesn't happen in my scenario before the doctor doesn't look at the scans
NZ doesn't have the screening capacity for when it's medically necessary, much less optional.
Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them. Yes, right now MRIs are expensive and false positives are common, but if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
There's a softer component to healthcare which is that people can overreact to medical results. If a doctor administers a scan, finds a handful of likely benign things but wants to administer another scan later on down the line, I'm probably much more likely to look for a second opinion that tells me to cut them out (even if it may not be medically necessary) than trust my doctor that "it's probably fine".
It's probably more accurate to use a software analogy about performance metrics. We measure random request spikes now and again that strain the system. It's probably fine, but later on down the line, something could change that results in an outage during one of these spikes. Do we proactively fix the problem even if no change is expected? Or do we wait till there is definitely a problem before taking action?
But surely this would decrease as we learned more from more frequent MRI scanning. Doctors and patients would be less likely to overreact, and we'd settle in on something better?
I'm not an expert though.
No, this is more like disabling logging because people are concerned the server is going down.
“Don’t worry about it, I don’t think it’s a real issue so we’re just going to ignore it”
But if you’ve never looked at the log before all these WARNINGs might be normal operation. It’s not turning off logging, it’s saying log at ERROR level.
That's a good point. How many people have a baseline MRI from when they were at their healthiest?
And if everyone had scans at their healthiest we would know better
Not to mention the malpractice risk and potential for extra income, which -- depending on where you live -- may strongly (if subconsciously) influence your physicians interpretations and recommendations.
Do you think a doctor is more likely to call something "possible cancer" and recommend that you either have a specialist do a biopsy (keeping in mind that many of these will be... hard to reach) or at least have a follow up MRI in 3, 6, 9 months?
Or tell you it's "pretty unlikely to be cancer, I don't think we need to worry about it" and then get sued for 20M when they are wrong about 1 in 100 cases (not to mention missing out on all the potential income from above).
At least in the US, the incentives here are grossly misaligned.
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The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality.
The reasons are complex, but the short answer is that cancer treatment is extremely hard on your body, and even if you don’t treat, stress can literally make you sick. I recommend reading The Emperor of all Maladies if you want to really get a sense for how delicate the problem of early screening is.
I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here.
The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects.
What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice. It shouldn’t be up to a health economist to make that judgement.
But who will pay for the hundreds of thousands of screening MRIs, along with the large number of incidental results that will require some sort of follow-up? Many patients will seek second opinions if not recommended to "cut it out", with additional costs also for the complications resulting from unnecessary biopsies. US medical care is already tremendously expensive; adding all of these costs will break the bank and for no real benefit.
> What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice.
What you're failing to capture is that this is a hard problem because it's both an individual choice and a collective one as well. Those "terrible side effects" might actually end up killing someone. You're choosing between a high-chance lottery on a small population or a low chance lottery on a far larger one. It's not that simple.
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Bot?
I appreciate that, but do wonder, if this is an issue with too much data or how we act on that data. In other words, could there be a future where we do have tons more data, but also use the data in such a way to achieve an overall better outcome for patients?
Maybe, but there's a human element that can make things worse too. Take prostate cancer as an example. Most men die with prostate cancer. Most men don't die _from_ prostate cancer. It isn't usually aggressive enough to matter. Most people aren't zen enough to accept that though, so just knowing that you have cancer can add stress to your life with measurably bad health impacts from the resulting hormonal changes (reduced immune function, impaired sleep, increased clotting tendency, slower wound healing, etc).
Ultimately its a balancing act between what we can know and what we can do about it. If you can’t treat a cancer (or your treatment is not effective, cf the radical mastectomy) then knowing who has it doesn’t help. As technology progresses and more cancers become readily treatable, it will make more sense to do early screening, and potentially full body MRIs.
But right now it is likely to cause a huge waste of time, resources, and yes, human lives to know about every little lump in your body.
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You’re assuming a future with highly competent specialists who also don’t make medical decisions based on insurance requirements.
Unfortunately too many radiologists and specialists are more focused on upping cash flow than medical care.
Then they should decide not to treat certain things and have better criteria around that than choosing to bury their heads in the sand and letting people die out of their ignorance.
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> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
> To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
The analogy is rather something like this: your downtime detector is not just a "ping" but a full web browser that tests everything and it sometimes flags things that are not actually issues. So you don't turn it off, but you only use it when you have another signal that indicates that something might be going wrong.
> Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
This is the main reason. Well technically the opposite of the main reason but more or less it's the same. MRIs are extremely high fidelity nowadays and as a result it's really really hard to read an MRI. Every person is different and there's a lot of variations and weird quirks. You get all the data rather than clearly identified problem areas like you get with say a CT w/ contrast, etc.
That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
> That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
How? How do you establish baselines? How do you build a classification of incidental findings? It's very possible that you'll find a lot of types and not a lot of representatives of each type. And then you have to correlate that to actual clinical results, but the population will be so heterogeneous that it'll be really hard to find an actual result.
It's not just "let's throw more data at the problem".
When I say establish baselines what I mean is to establish baselines for the individual.
If you have records of the locations and sizes of various atypical structures and forms throughout the body going back for years and all of a sudden one of them starts changing in size at a rate disproportionate to its history, that's probably cause to dig a little deeper.
It's certainly not "throw more data at the problem". Instead it's about giving the data a time axis with some decent fidelity.
> and all of a sudden one of them starts changing in size at a rate disproportionate to its history, that's probably cause to dig a little deeper.
That sentence is doing a lot of heavy lifting.
- What's "disproportionate to its history"? Obviously something going from 1mm to 10cm is worth checking out, but what about something going from 1mm to 2mm? Might be a tumor, might be that the position is just slightly different.
- What about other less measurable factors? Example, border features. That's harder to measure and things like movement or different machines can change how the borders of a feature look. How do you know what's a baseline and what's not.
- How frequently do you run these scans? It's likely that if something "starts changing in size" suddenly it will start giving symptoms before you have your next scheduled scan.
> It's certainly not "throw more data at the problem". Instead it's about giving the data a time axis with some decent fidelity.
It's definitely throwing more data at the problem, and you're assuming that it's viable to give "a time axis with decent fidelity". MRIs are much more complicated to interpret than people think, and screening is a much harder problem too. There are a lot of studies testing MRI imaging as a screening technique (among other techniques) and they don't always show an increase in survival rates.
We do not have a lot of MRI data. The average person probably gets a couple MRIs in their lifetime, and this is biased because we wait until something is clearly wrong to get the MRI. If you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong with them in the same general area and gets an MRI for that, and then just by chance also has the early stage cancer at the same time.
> we wait until something is clearly wrong to get the MRI. f you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong
Not always. There are bunch of studies for MRI screening in high-risk populations for specific cancers. There are scoring systems for a lot of them based on imaging features and they do find asymptomatic cancers.
In fact, if you add low-risk populations to the studies used to design imaging scores, you might end up adding more noise and making the study more difficult and the scoring less accurate.
> We already have a lot of MRI data.
That's true but not in a useful way for improving MRI screening.
What we have is lots of days from people who were sent to get an MRI because they had a complaint.
That's a very different group than people doing screening.
And the fact that they have a complaint (or have known risks) makes it easier to classify, compare and understand the data.
False positives trigger more diagnostics some of which can be harmful, not just psychologically but physiologically as well.
If false positives are ok, why not build a down time detector that rolls a die every 5 mins and alert on hitting a 6.
Additional diagnostics can also be very expensive. Articles like this don’t seem to understand the overall costs to a health system with decisions like these. And that cost eventually does go down into the pockets of patients one way or another.
I think the point of the conversation is that if we take the predatory capitalism out of the way, using MRIs could potentially be a net benefit overall for everyone.
I'd argue that malpractice risk has at least as much negative influence on a physicians judgment.
It's perceived as much less (medico-legally) risky to "do something" (or more often "refer the patient to someone else to do something") than not do something.
OECD data (most recent available, around 2020–2022): MRI units per 100K population: United States ~3.6, Canada ~1.0, United Kingdom ~0.7
I would argue that getting "predatory capitalism" out of the way has sharply curtailed MRI availability where that's been tried. Maybe we should loosen the leash on capitalism a bit to get better care...
> some of which can be harmful,
Like what?
I've seen instances where this is used as an excuse for what is, ostensibly, a trick to dimiss people using something that sounds vaguely professional. Like when doctors say they don't want to do additional x-rays because of the risk of radiation exposure, nvm that if it comes out slightly blurry they'll ask to redo it, or if you're cautious about it initially they'll tell you how it's not big deal and there's more radiation in a cluster of bananas.
Biopsies, radiation from additional scans, surgery, treatment for cancers that would not have developed further.
A lot of potential harms are at a societal level as well—from a public health perspective, if everyone starts having regular MRIs that produce incidental findings which require followup, you’re suddenly tying up lots of resources that would otherwise be available to actually-sick people. A person with symptomatic problems whose treatment is delayed because they can’t get an appointment because the specialists are booked full with incidental findings, that person is indirectly harmed by this.
The radiation from CT scans is not especially concerning at an individual level when there is a compelling reason for it, but, if we’re suddenly doing tons more to investigate incidental MRI findings, there may well be a point where those scans are causing a significant amount of cancer overall—a recent study suggested, I believe, that CT scans may be responsible for 5% of cancers already.
> Like what?
Well, from the original article: "And if someone is over-diagnosed, gets a biopsy and develops an infection, that's a direct harm."
Like when someone has an anaphylactic reaction to the contrast dye for their CT?
Contrast-induced nephropathy?
Gadolinium accumulation in the brain doesn't sound good for you...
Although I think this argument is usually talking about the risks of the resulting procedures (eg an injury or complication related to a biopsy done for a finding on imaging).
I worry particularly about damage to the kidneys, something that you mention in your comments.
It takes a lot to clear the dye.
A colonoscopy has the risk of going very wrong due to a puncture.
Harmful to shareholder value.
Personally I’d rather have cancer checked out rather than have a “wait and die” approach
The United States Preventative Services Task Force[1] reviews studies and meta-studies to make recommendations about screening procedures. Their ratings are used by Medicare and Medicaid to decide what's covered and for which patients. In turn, many private insurance companies cover the same procedures. The USPSTF explicitly doesn't consider cost in their recommendations. Most often, they look at whether a screening reduces mortality rates.
1: https://www.uspreventiveservicestaskforce.org/
But you're not having cancer checked out, you're having a "spot" or a "nodule" or something checked out.
And the person that's making the recommendation on whether or not to check it out may get sued for $10M if they tell you it's probably nothing and they're wrong, but have no harm come to them if they tell you it's worth having some other doctor do a biopsy.
And they might make an extra couple hundred bucks every time you have to come back and see them to follow up on this spot.
And the radiologist interpreting the MRIs... the same perverse incentives regarding how they interpret a "spot."
Insurance-based medical systems mean the patient has transferred responsibility for saying no to those actually paying the bills. They have to draw the line somewhere.
> ... if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
And if there's one thing where AI models really do already excel at it's classifying and noticing patterns.
Many dermatologists (not all of them yet, at least not in the EU), for example already have software classifiers using pictures of one's skin and helping guide diagnosis. I've lots of moles/nevi and freckles on my skin: I'm one of those Gen X kids raised by parents that had no idea that sun exposure and sunburns was a bad thing so I regularly get warning shots and my body, especially my back, if full of scars for for my entire life dermatologists have regularly removed concerning little buggers and sent them to the lab for further analysis.
Nowadays my dermatologist is helped in her classification by hardware/software.
I don't see why that wouldn't be the way forward for full scan MRI: they'll begin to be more and more hooked up to AI classifiers.
It always takes time: it's not as if the tech comes out and in 48 hours every hospital/physician is equipped with it.
It's literally the future is here (classifiers helping dermatologists find concerning nevi), just not evenly distributed (many dermatologists still don't have access to these latest machines).
I can't imagine this taking strong hold in the US unless it shields physicians from legal consequences of false negatives or produces enough false positives to ensure revenue doesn't fall.
I don't see any way that the hospital systems running healthcare in the US would embrace a technology that reduces false positives (income) without decreasing false negatives (risk and lost income) at least as much.
> Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them
More and more European countries are currently adopting Lung Cancer screening programs. It's usually limited to people with a certain amount of cigarette-pack-years, but still gives the opportunity for driving more of the innovation you're talking about. I think the main challenge at the moment is that nothing in healthcare is prepared of looking at those scans effectively, a radiologist has full medical education + additional specialization - without effective procedures you'll never be able to provide full-body scans with any meaningful impact.
It's helpful in justifying screening that non-small cell lung cancer treatments have greatly improved in recent years.
It’s expensive because superconducting magnets cryogenically cooled in liquid helium are expensive to build and run. No amount of demand signal will overcome that reality.
Not just cost also time. When I had my scan it took 45 minutes and two trained nurses.
Ofcourse in America poor people don't have access to healthcare so it's a lot easier. But in a universal healthcare system everything has to be rationed.
But medicine isn't quite the same feedback loop as downtime monitoringg
This isn’t just about false positives.
Most people do have things “wrong” with their body, but they are asymptomatic. The human body can and does cope with a certain amount of failure and/or anomaly as a part of normal operation that we otherwise consider healthy.
The problem is that this information is often not actionable. An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems. The way the body naturally responds to problems doesn’t always look perfect on a scan but if it results in no symptoms it is the best result. And for most asymptomatic findings, taking an invasive next step has more risk than the finding itself. And these findings will always be in the back of the patients head, whether relevant or not, and might complicate how they seek care for other real issues later on.
> An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems.
Its the doctors doing this, not the MRI.
There's this weird definition switch that always happens with the "overdiagnosis" defense where the information gets blamed for the overdiagnosis. An MRI doesn't provide any diagnosis in any sense of the definition. A doctor does.
Claiming an overdiagnosis defense is essentually implying the medical industry is worse for most than doing nothing.
Yeah, any doctor worth their salt is going to be diagnosing you based off of the MRI results and some other evidence.
But in the scenarios this article is talking about (Prenuvo, et al), these aren’t scans ordered by a doctor, and there is no other evidence. It is just a patient getting some MRI findings of unknown clinical significance dumped in their lap.
The problem isn’t an overdiagnosis by doctors. The problem is that there’s no doctor diagnosing anything in these instances.
Same logic as not treating the cancer of an 80 year-old as a heuristic rather than looking at the health, genetics, and epigenetics of the individual beyond the chronological age. Whatever happened to "personalized medicine?"
This article sees methodological failure, I see training data. Training data that could ultimately be used to refine low resolution scans into targeted high resolution scans as needed driving down costs and driving up accuracy. We've already demonstrated AI upscaling, what's the blocker to doing the same for MRI?
And finally, who are any of us to tell people what they can do with their money? China has these things down to $70. And they're leaning in hard on improving them. Cue obligatory China cuts corners blah blah blah. Sigh.
Answering the question in the title...
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
So a bit less than 1.8% of the time in this study
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer.
That's 2.0%
Note that this doesn't mean that 1.7~2.0% of people have cancer without knowing it. It could be more:
> A negative scan doesn’t mean you’re disease-free. Some cancers and conditions simply aren’t visible yet or aren’t reliably detected on a one-time full-body MRI."
But also perhaps less, in a way:
> "You're finding something that never would have caused you any problem in your life, and in cancer, we call that overdiagnosis," Vickers says.
Yep, I have experience with both. It found cancer for my wife and she was able to treat it immediately. Fully recovered.
It found a weird spot on me that turned out to a pancreatic rest.
The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year . We knew nothing was guaranteed but we wanted to do some tests.
> The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year .
Interesting. If it's not too personal, would you mind elaborating on the kind of life decision you were making?
I have never heard of anyone getting checked up for cancer before they make an important life decision. I mean won't a cancer diagnosis disrupt your life anyway?
Not sure if you will see this.
We were buying a sailboat(we actually did it). Wife got diagnosed with cancer. We talked with doctors about treatment, felt confident with catching it so early.
Purchased the sailboat, we live on the sailboat with our two kids, two dogs, and two cats, 6+ months out of the year.
What you can't plan for is shit that happens on land. We came back in June 2025, my wife was stopped at a red light and got rear ended by a dump truck. That has put a pause on our sailing life. But we should be getting back out there soon.
[dead]
> You're finding something that never would have caused you any problem in your life
Is it though? Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
There's a theory that the first-stage cancer is way more common than we think, it's just doesn't develop further most of the time, cause no symptoms and remains undiagnosed throughout the lifetime.
There's some support for this view because agressive screening for thyroid and prostate cancers increases the number of surgeries a lot but doesn't seem affect the mortality rates.
Risks from a surgery are non-negligible, if you perform it to treat a low-risk condition it may be a net loss in the end.
So you're technically right about the "early-detecting" part, but the "much easier to treat" step is problematic because it's unclear what a net-positive treatment looks like for low-risk cases. Probably it comes down to yearly monitoring of whatever was detected, not the actual treatment.
Yes, you could early-detect something, but the likelihood of this thing being life-threatening are extremely low. If you choose to manage this thing aggressively anyway, you have to undergo more invasive testing (e.g., biopsies, surgery, anesthesia, etc.) that all have small risks of catastrophic events. In most cases, the risks of more invasive testing outweigh the risks of just not pursuing any further workup.
Nothing in medicine comes for free—everything is a tradeoff.
> Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
It could be. It could also be the cade that you undergo invasive surgery for something that would have never caused you problems within your life. The problem is that cancer isn‘t cancer. Even if it originates from the same tissue, some tumors behave very different from others.
>"More men die with prostate cancer than because of it" - an old adage that still holds true in the 21st century
https://pubmed.ncbi.nlm.nih.gov/33360667/
Yeah a 2% risk of having something which can easily kill you and is very expensive to treat, especially if you're not elderly and still have lots of life ahead of your, is not exactly trivial. I would want to know about this
That's not the case. Most of these wouldn't kill you. Many of those that would kill you would be spotted in time anyways.
And the few that would kill you and would otherwise not be noticed are so rare that the risk of the procedures on the others is considered higher.
Doctors here are cognitively captured by a system designed to limit cost (and that's mostly a good thing)
But scanning frequently is overwhelmingly good for the patient. The problem is the doctors. Imagine two possibilities. 1. You scan every six months and a doctor reviews your scans but never tells you anything no matter what 2. You scan every six months and a doctor reviews your scans and only tells you results if you have an obviously growing mass that has a probability greater than 95% of being cancerous
Obviously #2 is better for the patient than #1, but #1 is equivalent to never testing if you ignore cost.
So the actual reason we don't have effect frequent scans combined with effective diagnostic techniques is cost, and doctors cope with this reality by saying clearly wrong things about "over diagnosis". It's a local minimum of the payer/provider dynamic that has nothing to do with scans per se.
Why is it good for the patient? I think that to claim this, you'd need to show a difference in outcomes.
Here, you have a tool with a ~100% false positive rate, so if we start administering it to everyone, it will almost certainly cost lives. Botched biopsies, unnecessary treatments, other complications. Not to mention the huge cost that would divert money from other welfare programs. So you need to show that when it actually detects something, it saves at least as many lives. And I doubt that's the case.
I wouldn't argue we should roll this out to everyone. But I am glad it exists. I commented earlier in this topic about how it caught cancer in my wife at the age of 44. She didn't have to go through chemo or radiation treatment because it was caught so early. Surgery removed the whole cancer.
Additionally for me, I have a scan that shows what my body currently has. I had something show up that I did get a scope to check out that was a pancreatic rest. No big deal. Now, if I ever have another MRI and somethings is somewhere else, we have a baseline to compare against. Everything is a risk calculation. When I did my MRI, I also had other procedures done like a heart calcium score.
I will get a little more personal. We didn't do it out of the blue. My wife and I decided we want to live on a sailboat. That was a big purchase for us and boats take a long time to sell. We didn't want to commit to such a purchase then 1 year later find out either of us had cancer then we have the stress of cancer and the stress of trying to sell a boat.
I would never suggest everyone do it, but I am happy we did.
You are deep in the cope here.
There is no world in which biopsies cause more harm than detecting every cancer at stage 1 prevents.
> Not to mention the huge cost that would divert money from shareholders
Ah, that explains it
I’ll give you a counter example. I had an MRI of my neck for unrelated reasons. It found a thyroid nodule with suspicious characteristics. Incidentally I had had an MRI of the same areaa few years before and it wasn’t there.
So I had a biopsy. Which was equivocal also.
So I had it out which involved removing half my thyroid. Turns out it was a cancer but like the least serious kind, in fact the classification of it as actual cancer has gone back and forth over the years
But my other half of my thyroid couldn’t produce enough thyroid hormone, and now I have to take thyroid replacement the rest of my life to start alive
Also the surgery affected my voice and I sound like RFK jr now.
I clearly suffered some harm, and even after having the thing out, it’s unclear if that was beneficial at all. A large proportion of these kind of tumors quit growing and never do anything bad. But some do. So who knows.
Was the tradeoff worth it?
I don’t think it’s possible to say
Did you read my two options? Do you agree option 2 is better than option 1? If so, then scans are better than no scan
You don't need to show that it's possible to avoid false positives. That's doctors being irrational.
You only need to show that it's possible to build a diagnostic system that's better than no testing, and I have shown that already
No. To argue for the benefit of the procedure, you need to show a difference in outcomes. Not that it can detect something, even if it could (which whole-body MRIs clearly don't). That the detection improves your chances of survival.
If you have an growing mass in your body, then if it's cancer, after a year, it might be too late for treatment. Or it may turn out to be nothing: a benign tumor / cyst / fat deposit in an unusual place. Or it may be slow-growing prostate cancer that you can live with for another 20 years, and maybe it's the chemotherapy that will do you in. It's really not that clear-cut in medicine.
To give you have another example: let's say that the risk of appendicitis in people who have an appendix is 1%. And the risk in people who had an appendix removed is 0%. Does this justify proactively removing the appendix? No, because the consequences of complications are much higher than the harm you're preventing. The same applies here: detection, even if 100% accurate, doesn't mean anything. You need to show that what you do with the result actually helps.
The difference in out come is
With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies Without my change: many of those 95% die, the 0.5% do not get useless biopsies
And the beauty of this is you can pick the percentage!
> If you have an growing mass in your body, then after a year, it may very well no longer make a difference whether you treat it or not. Or it may be that you would have lived another 20 years just fine
This is just wrong for many parts of the body. In your brain? Your lungs? Growing for a year between 3 scans 6 months apart? Extremely unlikely to be benign
> The same applies here: detection, even if 100% accurate, doesn't mean anything. You need to show that what you do with the result actually helps.
This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
> With my change: 95% of people who are shown scans have cancer and are treated earlier. Without my change: many of those 95% die
Why? What happens if the cancer still doesn't respond to treatment even when detected early? Or, to the contrary, if the cancer also responds to treatment when it starts becoming symptomatic?
That's why we have studies to understand if screening is a good practice or not. It's not that clear cut.
> With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies Without my change: many of those 95% die, the 0.5% do not get useless biopsies
You assume that treating cancer automatically improves the outcome. Treating cancer often kills you, so treating a non-fatal tumor can easily be a bad decision. And a lot of the tumors found by agressive scans are like that, but we don't know yet how much exactly and how to tell one from the other. It's a new question that requires decades-long observations to answer.
> This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
You're saying it as if detection somehow cures cancer, it doesn't.
> You're saying it as if detection somehow cures cancer, it doesn't.
No, I didn't say the detector would cause cancer to be cured. I said fewer people would die with no downsides. If treatment is sometimes harmful then the detector also fixes that, you'd never treat people without cancer
No, the detector doesn't fix that, that problem is not treating people without cancer. The problem is treating people with cancer that won't kill or harm them during their lifetime. In this case even a low risk treatment becomes harmful, let alone cancer treatments.
Your claim is equivalent to claiming that most cancer treatment is net harmful btw
and this is obviously false, especially for cancers detected earlier
Whether treatment is net harmful or not depends on the level of the risk with no treatment. If you apply treatment with 15% chance of severe side effects to a tumor that will kill the patient with 50% chance in the next five years, of course it's net positive. If you apply it to a first-stage cancer that has 10% chance of progressing to the second stage, the very same treatment will be net harmful.
So no, most cancer treatments aren't net harmful now, but they likely will be in a world where your programme is implemented. Even something as "simple" as biopsy has mortality rates far from zero. Applying it at scale may not have the effect you expect. And surgeries and chemo are much worse.
But do you see how crazy that sounds? If we know the numbers, we would just not do the treatment in those cases.
And in reality it's not actually close like this. Early treatment is so overwhelmingly better than it completely dwarfs all considerations of biopsy risk.
Late stage lung cancer has less than half the 5 survival of early stage, and around 50% of lung cancer detection is late stage. That's around 30000 lives you could save every year from just lung cancer.
Let's say you don't protocol for all adults. Typically post CT or PET at most 10% get a biopsy. So let's say we increase the false positives that lead to CT or PET by X% of adults. That's 270M * X additional biopsies. Lung biopsy mortality is under 2%.
So the worst case you need a false positive rate under 5% for this to he net beneficial for lung cancer. That's low but with 3 scans 6 months apart and a good radiologist, it's not unreasonable
I believe I've assumed the worst case for all the quantities. In reality the addition screened people would have much lower CT detection rate than the background population, and biopsy mortality has been decreasing. Plus you can do this for only people above 40 where the benefits are higher
Yes, IF we know the numbers, that's the whole problem. Unprompted full-body MRI scans turn up a completely new probability distribution. We CAN'T know the numbers as of today, it takes decades of controlled studies to get them. (Which is exactly what doctors advocate for)
Even for something as studied as colon cancer it's still controversial whether mass colonoscopies are better than occult blood tests. US sticks to the former, Europe to latter. US have higher rates of polyp removal, higher rates of cancer detection, higher rates of surgeries and ... higher mortality rates than EU. Why this happens is being studied today, there are some early results. What is absolutely clear though is that higher detection rates don't automatically lead to better outcomes, it can easily be the opposite.
Or take something as simple as sunscreen. It's well-known that sun exposure for light-skinned people can cause cancer and sunscreen is advised. A few multi-decade studies have shown that while it indeed eradicates the skin cancer it also shortens the life expectancy by a few years.
Primum non nocere, doctors and scientists are unsure whether sunscreen should be applied at scale and you effectively call for mass biopsies and surgeries.
So if this is true, it seems that we must accept that many people will die of cancer we could have detected and cured with frequent scans, because doing frequent scans will overall cause more harm to people who didn't need treatment. So the overall death/harm rate would be worst with more frequent scans?
Isn't that then just a problem with the scan and diagnosis? With more frequent scans it seems highly unlikely that we wouldn't improve this process and end up in a better place.
No.
When there is low prevalence of a condition, but a non-zero false positive rate of a test, the false positives generated by universal testing can in fact be a net dis-benefit (worry, invasive further procedures, etc) to the patient population as a whole, regardless of cost. This is a well understood statistical phenomenon, and is carefully considered by healthcare systems when advising on testing.
Read my #2 option, which accounts for that
As if there was an easy, foolproof and precise way to calculate these probabilities. "Just only alter the patient when it is appropriate" he said. You can solve all the world's problems this way, just "always do the right thing". Reality, unfortunately, is more complicated.
What if in reality the doctors can only say if the probability is above 60% or not? What if some doctors are better than others at estimating probabilities? What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
> What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
It's this one
It doesn't matter that some cancers are hard to diagnose. What matters is that some are not hard, especially if you have multiple scans spanning several years
Did you know optometrists now scan your retina during ordinary eyeglasses appointments? They didn't do this in the past because it was too expensive. But optometrists cannot diagnose or treat based on these scans. They refer you to an opthamologist.
Some day your PCP will do the same with MRIs, but only once they are cheap. For now only rich people have this luxury
I don't think this is doctors being captured by the system so much as medicine being cautious about scaling interventions without strong outcome data
Nope, this is cope
Tons of diagnostic interventions have been scaled without strong outcome data. For example many clinics now do fractional exhaled nitric oxide (FeNO) tests because they are safe, fairly cheap, and patients often pay directly out of pocket so they are easy to make money on.
But the evidence for the diagnostic usefulness of this test is extremely low, multiple meta analysis have concluded.
The reason FeNO tests are done but not MRIs is because FeNO tests are $40
"First, do no harm."
Your case #2 doesn't have nearly enough information to say whether it's obviously better for a population of patients. There are a lot of other variables you would need to know:
Saying that doctors are lying about over diagnosis to cope with the fact that diagnostic techniques are too expensive is absurd. They have to actually make decisions in the real world, where your two neat little categories can't be known even if they hypothetically exist.Best comment here
Can someone ELI5 why false positives on a MRI are so bad?
From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight.
At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups?
I get that ideally we'd have a crystal ball with 0 type I / type II errors but short of that, why is a noisy predictor bad?
> At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months
If a doctor even _hints_ there might be cancer, the patient will have a terrible 6 months (with actual, measurable negative health impacts of the added stress). Also, at some uncertainy-level (say, 10% chance of cancer) the doctor _has_ to say something and has to schedule expensive followups to not risk liability, even though in 90% of the cases it is not only unnecessary, but actively harmful to the patients.
When, on average, the cost of the screening + the harm done by a false positive outweighs the benefits of an early detection, you shouldn't do the screening in the first place.
I 100% agree. The UK recently recommended to not scan for prostate cancer because it sometimes detects cancers that don't need treatment:
https://www.bbc.com/news/articles/cm20169gz44o.amp
This seems super dumb to me. If the test detects cancer that doesn't need treatment, don't treat it!! It's still better to know it's there and that you need to monitor it.
> Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time,
Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
My parents are doctors so I’m very used to giving them all the data and pushing decision making down to them. Almost all of the time there is no action to be taken. But this built a certain habit that I realized is not conducive to medical care in the US.
I once told my wife that it’s better if she just passes all information downstream and then lets the diagnostician do the diagnostics.
During her pregnancy, at antenatal monitoring, when asked the routine questions I encouraged her to mention everything and so she mentioned a slight twinge in her chest (“it’s probably nothing, maybe something I ate”). She was hooked up to the monitors and so on but this was a sudden moment of panic for everyone but us. The nurse called for a doctor, there was an EKG machine brought up, all sorts of honestly nonsensical reaction given the data.
I realized my mistake soon after. There’s the obvious legal consideration, of course, but the real magic lies in the fact that no one gives full information so if someone sends you a signal they assume it’s crossed some threshold to significance. My mistake was in being a non-normative participant here, akin to someone who drives straight on green in a land where a green light means you first let one person turn left before you go.
Anyway, patients are supposed to perform pre-diagnosis in the US. And you’re not supposed to show your doctor things that they will then act on. You should first apply Bayes yourself and then give the info to the doctor here because they won’t use Bayes.
> Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
I think what's happening here is that the smoke detector is indicating the possibility of fire, but the toaster is always being immediately doused in water. Which as we know would cause more damage than good unless there truly was a raging inferno.
The suggestion here seems to be moving the smoke detector to somewhere where there's a higher chance of it ringing means a higher chance of a damaging fire. Which seems quite reasonable.
The question is how can you know if it needs treatment or not. I guess you either need to do a biopsy, or check if it's grown after N months (leaving patient scared and anxious during that time). Neither are great if most cases end up not needing treatment.
If the test provides you zero information about whether it needs treating then it was never a useful test. Presumably it's more like "there's a X% chance this needs treatment". In which case you just set reasonable thresholds for X. E.g. if it's 5% you monitor it, 10% you do a biopsy, 70% you operate, etc.
This is much more sensible than just not testing at all and letting people die from cancer.
> leaving patient scared and anxious during that time
This seems to be the actual motivation. We don't want to scare people with test results so we're just not going to test them. I think that should be up to the patient.
> This is much more sensible than just not testing at all and letting people die from cancer.
This is not what happens. You're assuming that if the cancer does not get detected by the screening then it never gets detected. What actually happens is that the test gives information that might actually be redundant and obtainable in less risky way. What the studies are showing is that waiting until there are other, more specific signs and symptoms of the prostate cancer results in the same survival rates.
Interesting. Do you have a source for that?
See https://pubmed.ncbi.nlm.nih.gov/38926075/. I was not aware of the ERSPC which came out late last year and gives better outcomes for screening, but overall the evidence is not super clear yet. There are possibly certain groups that can benefit from PSA screening more than others. Also, modern, more effective treatments might allow for later diagnosis with the same clinical results.
> If the test detects cancer that doesn't need treatment, don't treat it!!
How do you know which ones to treat and which ones to leave?
When the result is above a chosen threshold (which may depend on other factors like family history etc.).
Unfortunately that "chosen threshold" is really hard to know, specially if you want to balance individual and population level necessities.
My understanding is it's liability, if the doctor decides not to look into it then they could be blamed for it if it turns to cancer.
Because the patient is usually unable to handle such information correctly (the medical system sometimes too). And the whole-body-scan type of tests additionally pre-select for the high anxiety types.
In real life, every additional data point has a cost...
I pay an extra $60 a year to have my ophthalmologist take a digital image of my retina. It comes back as normal every year, but if something does change we can diff the image against the baseline.
Maybe I don't want to look for cancer right now but if I spend $1,000 every 5 years to take an image for later use... isn't that useful?
Yes, and it seems like its purposefully ignored in the "body scan" debate. full CT scans would be more problematic, and MRI's (especially no contrast ones) don't pick up a lot of things... but having annual comparisons over a few years would likely fill in some of those gaps. literally and figuratively.
Might be, but in the context it's also worth asking what better options you have for your health with that $1000.
(for some people that question may not apply, of course, but at a population level it does, and we have population-level questions about effective use of MRI time.). And if there's something better, you should spend it on that and then ask the question _again_. So it could be that getting a whole-body MRI is something like $30k down the list of best ways to spend money for improved health.
I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
> I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
Spending 1k on a gym membership and more fresh vegetables would be a pretty high return on investment, if one isn't in shape and eating healthy already.
Er wait is retinal cancer a thing?
Yes. Like OP, I do a picture every year. Three years ago there was a scare, that turned out to be nothing.
Retinal imaging is used to detect damage from glaucoma or other eye disease, by "diffing" the fine blood vessels and nerves.
Family history of glaucoma and macular degeneration. Also had a semi detached retina when I was a kid.
Yes. You can also have melanoma on your uvea
theres a ton of degeneative stuff too that's not strongly age corrilated.
One important point is that many people die WITH cancer but not OF cancer. So even for the 1.8%, only a fraction of those people were going to die of the disease (or even suffer significant symptoms) - the rest were just going to die of natural causes anyway.
But now you've found it you pretty much have to remove it, which has significant quality of life implications.
This seems like a wild statement.
Age is a big factor in the with/of cancer factor. If someone is 80 years old then there's good chance it won't be cancer that kills them (assuming they aren't already in a late stage).
But if you are 40 and you have cancer, there's a good chance you'll die of that cancer if it's left untreated.
I'm personally of the opinion that cancer screening should happen earlier for younger people and less frequently for older people. Like, if you hit 80, there's really basically no reason to screen for cancer.
It does, doesn't it! This is basically the reason scepticism in screening has risen (amongst scientists and medics, not the general population) - research seems to show that screening catches much more cancer but doesn't save many more people.
Rohin Francis does a good video on it, which you don't have to watch because it has references underneath you can click straight through to (the video is good though): https://youtu.be/yNzQ_sLGIuA
I am frustrated by this because it seems obvious to me that "more data == better" but I guess it makes sense if you think of the scans as having high amounts of noise, and us having a poor understanding of the system we're monitoring (this never happens in tech, of course :)).
From the statistics on autopsy and other accidental discovery, it seems that more than 30% of the population has some cancer by age 40 that would never impact their life left untreated (mostly thyroid, prostate, and surprisingly-for-me, breast cancer). Regular widespread full body MRI might catch these, but the effects of treating (e.g.) prostate cancer are so terrible that most would be better off ignoring it.
Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans? It seems like that addresses much of the harm that a false positive can cause (invasive biopsy leading to complications) while maintaining most of the gains (still very early detection).
The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something off. But you can‘t really reschedule everybody constantly, as that would entirely break the concept.
"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper.
So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much.
Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
I totally agree. US healthcare is broken and costs aren't tied to the reality of how expensive something actually is. I have very high hopes that modern medicine is in for a massive disruptive change where things like full body MRI, along with analysis, could be done very cheap and with no admin overhead. In that model 'we see something we aren't sure of. It is probably nothing but to be sure we want to do follow-ups' is far less of a problem.
A lot of this however is how it is discussed with the patient. Discussions about the likelihood of there being a real issue when something is seen need to be clear and informative without being alarming. 'We did a routine scan and these often show transient artifacts that turn out to be nothing, but in an abundance of caution we want to do a followup' is totally different than 'we saw something we are concerned about and need to do a followup'. How things are messaged really matters.
> MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
How would this work?
I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2.
I can also do an MR scan. It took a fair bit of training and the scanner and scan room cost about US$2 million. Service contracts on the scanner, scan room, chillers and required staffing utterly dwarf the cost of the scanner over its lifetime.
The scan takes 20-75 minutes. Then the images get sent for reporting. Unlike a blood test, reporting isn’t automated. Even if it was, how could availability of MR ever be similar to a blood test?
> I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2.
This depends on a blood test. Bacteria cultures or PCR tests still take more time.
A mid-range scanner costs $500k, the room itself indeed might cost more. Just as real estate. Scanners are just not scarce anymore, there are even sites that sell used ones: https://prizmedimaging.com/collections/mri-equipment (I now want one in my backyard...)
You can lease a new top-level device at around $30k per month: https://www.meridianleasing.com/equipment/medical/mri-machin...
So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible.
A full-body scan is about 1 hour. But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes. So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session.
This is literally in the "blood test" expenses range.
> Unlike a blood test, reporting isn’t automated.
Radiology readings is one thing where AI is already making inroads. And radiologists can be located anywhere, it's a perfectly remotable job.
> Even if it was, how could availability of MR ever be similar to a blood test?
Yeah, indeed. How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building?
Mass production happened. And this time it has taken the industry completely by surprise.
I manage an MR service. Not a large one, but it keeps me busy.
>A mid-range scanner costs $500k, the room itself indeed might cost more. Just as real estate.
The room is about $250k to get it fitted out and the Faraday cage built.
> Scanners are just not scarce anymore, there are even sites that sell used ones: https://prizmedimaging.com/collections/mri-equipment (I now want one in my backyard...) You can lease a new top-level device at around $30k per month: https://www.meridianleasing.com/equipment/medical/mri-machin...
The Skyra is end of life and the ones I know of are getting pulled out. Too old. The generation after it is getting on too. The new generation will appear next year. Likely ‘dry’ magnets - low helium usage. The Siemens 1.5T has already had this upgrade.
> So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible.
A service contract is expensive and also required. I’d expect them to be up to about US$75-100k a year. Coils are US$10-20k each and a scanner has about 10 different ones. We blow about one a month across our scanners and get them replaced. Various things break, and it comes in waves. In recent months: the body coil blew (this is a big deal, $150k?), gradient amp, amp cables, helium expansion vessel, vacuum pump, bore screen, knee coil, another knee coil. The service contract covers all the repairs.
>A full-body scan is about 1 hour. You can do them in 30-45mins, improving the business case.
But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes.
Doing a real scan of a body site is vastly better, and is about 20 mins per region.
> So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session. This is literally in the "blood test" expenses range.
We get around that number out of our scanners doing real scans and our costs are a lot more than that.
I don’t see staffing mentioned? A good tech will improve throughout, and you need more than one. A good operation will have several per scanner. They reduce the ever present danger and keep the operation running smoothly. I’m biased, I’m a tech.
Another thing missing - liability. I work in a country that isn’t quite as full of lawsuits as the US. Whole body scans are a glorious way of collecting liability. Poor quality images of everything in ‘well’ patients. As a rule in imaging, ask a good question get a good answer. When you’re searching the whole patient for something’s it’s easy to miss something.
> How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building? Mass production happened. And this time it has taken the industry completely by surprise.
The radiologist needs to be onsite. We give drugs. They inject things, they biopsy, they are doing stuff.
Yes, lots of stuff can be done remotely and AI assisted. Assuming they can all be replaced assumes a role that the radiologist had a long time ago, or maybe never had.
There are a lot of efficiencies that can be made, and radiology needs all the help it can get, but it isn’t a ludicrously inefficient or stuck in the past.
> I don’t see staffing mentioned? A good tech will improve throughout, and you need more than one. A good operation will have several per scanner. They reduce the ever present danger and keep the operation running smoothly. I’m biased, I’m a tech.
That's why I put the cost of the scan at $1k, to make room for a profit margin and the staffing cost (which will be more than equipment).
Liability is an issue, but not an insurmountable one. If you get poor-quality images, you can just retake them. So biasing radiologists towards that can be a workable solution. There is also a lawsuit in the US going on against one of the full-body scan companies that missed a cancer, so we'll see how it turns out.
> The radiologist needs to be onsite. We give drugs. They inject things, they biopsy, they are doing stuff.
For clinical MRI. Not the diagnostic screening ones, they are done without any contrast.
> There are a lot of efficiencies that can be made, and radiology needs all the help it can get, but it isn’t a ludicrously inefficient or stuck in the past.
Radiology is fine, the AI will help them to do quick screening and point out possible pathologies.
I think you're missing the point. The psychological cost of a conditional-positive result is nonzero, and can be very significant (I speak from a little bit of experience here). But far more importantly: the physiological cost of invasive followups when you eventually trip the threshold of "time to go explore with a scalpel" is very high, and the missing evidence this story is about is whether you can get to that threshold with an MRI.
Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
> Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
Again, _all_ you need to do is to make a follow-up scan in 1-3 months to see if there are any changes. It's a preventative tool, so unless you have other indications, it's almost always safe to wait for a bit.
And yes, it requires educating patients that sometimes just waiting and doing a follow-up scan is right. And yes, I also have a personal experience with that (I had an "idiopathic lymphadenopathy", aka "we don't know WTF is going on").
It's a good thought experiment, but what you really need here is a randomized controlled study to see if your new plan results in better outcomes, before you roll it out to the whole world.
* Doctors and medical researchers keep saying that routine MRIs for non-symptomatic or low-risk patients is a bad idea, because the outcomes are worse than not scanning.
* There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy.
* Nevertheless, here we are, nerds arguing we know better than all these people.
And I don't buy that. EXACTLY this was also said about prostate cancer screening. Word-for-word. "Overdiagnosing", "people are better off not knowing", "psychological burdens", "invasive procedures", etc.
Now we have multiple longitudinal studies of people receiving aggressive screening and the usual standard of care. The aggressive screening group, unsurprisingly, has better outcomes with less mortality.
> * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy.
Yeah. I guess it's time to stop using fire alarms. People are better off not knowing if a building is on fire, and frequent false alarms have a negative effect on psychological well-being.
Just look at the risk of burning to death. Alarms make no sense at all!
> * Nevertheless, here we are, nerds arguing we know better than all these people.
Yes. Absolutely. And I actually have read (I think) all the studies, and came thoroughly unimpressed. They're utterly sloppy with poor statistical analyses.
It's absolutely an indictment of the medical industry that has become so crusty that it can't be bothered to integrate new diagnostic modality. That is the _only_ way to detect multiple lethal cancers while they are still curable.
You're not engaging with the logic. Stipulate that it is the only way to detect multiple lethal cancers. If you end up harming more people than you help, the intervention is bad. Right now, you're only looking at one half of the balance sheet.
> You're not engaging with the logic.
Ditto for you.
> Stipulate that it is the only way to detect multiple lethal cancers.
This is trivially true.
> If you end up harming more people than you help, the intervention is bad.
The only pathway through which diagnostic MRIs can feasibly harm people is aggressive follow-up of uncertain findings. And this is almost completely solved by just doing another scan several weeks/months in the future. With corresponding patient education.
This is literally all what was needed in the case of prostate cancer screening: less aggressive biopsies and bias towards observation rather than action. Yet it took _two_ _decades_ to arrive at this point. And some doctors _still_ refuse to order screening tests out of this misplaced idea of "not knowing is better".
And this is not the only time when "geeks knew better". For example, checklists for surgeries are a no-brainer to anyone with an aviation background. Yet they became standard only two decades ago ( https://pmc.ncbi.nlm.nih.gov/articles/PMC6032919/ )! Over rather strong objections from doctors.
The people arguing against routine MRI scans are the checklist people!
But, look: if you think routine prostate screening is a good idea, I don't have a counterargument. You're right: there's already an emerging discipline of watchful waiting with prostate pathologies.
The argument being made here is about full body MRI scans: doing a dragnet sweep looking for neoplasms anywhere and everywhere. Not the same thing! Similarly: my belief that the EBM people are right about full-body scans doesn't mean I oppose colon cancer screening!
> The people arguing against routine MRI scans are the checklist people!
Are they? They seem to be exactly the same set of people who resisted them ( https://pubmed.ncbi.nlm.nih.gov/22069112/ ).
> The argument being made here is about full body MRI scans: doing a dragnet sweep looking for neoplasms anywhere and everywhere. Not the same thing!
It's exactly the same thing, but on a larger scale. Yes, it will likely require at least some adjustment to the standards of care and development of more stringent criteria for follow-up procedures. But we're already talking about fine-tuning, rather than something fundamental.
Here's a study from one of the providers:
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer. Of these cancers, 68% didn't have targeted screening tests and 64% were localized when detected. The company says it finds possibly life-threatening conditions in 1 in 20 people.
So we're talking about the real-world 4% rate for biopsies, with about 50% false positive rate. This is not that far removed from the current clinical 30% false positive rate. And this is far from the apocalyptic scenarios of multiple biopsies for every patient.
And the psychological burden appears to be modest: https://pubmed.ncbi.nlm.nih.gov/33279799/
While the negatives cited by doctors are:
> To date, no study has been performed that rigorously investigates the impact on disease-specific survival following whole body MRI in asymptomatic patients without specific risk factors, and no study has been performed to confirm that a ‘negative’ whole body MRI excludes significant disease 5 or more years’ later.
I read most of the studies that are cited here: https://www.ranzcr.com/college/document-library/2024-positio... And I have not found a single one that had anything really negative about the MRI consequences. And half of them are outright positive endorsements: https://pubmed.ncbi.nlm.nih.gov/33216779/
The only real remaining argument is cost effectiveness of MRI, especially for government-based healthcare. It is a valid argument, but it's beside the point for people who are self-paying. And it's also missing the implications of economy of scale.
So I'm pretty sure in this particular case the geeks indeed know more than doctors.
This is pretty much what the experts say:
https://www.ranzcr.com/college/document-library/2024-positio...
> Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans?
Doctors have already thought of this. Several issues with it:
* Monitoring still causes anxiety and mental health issues which come with real effects on patient's quality of life. It's not "harmless".
* Unclear when to monitor and when to treat. It's also really hard to get enough data to characterize these early unspecific findings enough to get confidence on what to do.
* Monitoring via MRI might be just as useful as monitoring via symptoms or any other "passive" methods that do not require a previous scan.
There are two points in MRIs that limit or (better) regulate their use:
* financial cost vs level of care. A full body MRI costs a huge sum but it is the most detailed non-invasive diagnosis we have for any disease that can lead to earlier therapy. Used as a screening method, does it worth to save one patient in tens/hundreds tests performed? You answer, but public health authorities, health insurances and medical societies are negative.
* MRI shows some minor findings that would never cause symptoms and better not be known to the patient due to the stress they bring and cost of ongoing follow up (eg in the brain small meningiomas or angiomas). This might bring more harm than good and limit their net value.
For some reason, I always found the arguments for "it's better to not know" for these tests to be strange and slightly infantilizing. But of course this must not be the end of it, and there might be some more well thought out arguments from bioethicists that go beyond "the patient can't handle the truth". Because this argument seems like it's doing a lot of heavy lifting without much evidence.
“slightly infantilizing” might be an appropriate course given how well LLM sycophancy works on the general populace.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer
So that would be 1.71% of people getting a full body MRI catching cancer early.
That seems like an astoundingly good return to me. What does late cancer treatment and lost lives cost? Many times these MRI’s.
If everyone did this, would there be any significant number of late stage cancer discoveries anymore?
Obviously, reducing the cost of false positives is important. But if 1.7% of us have cancer - wow. My guess is that percentage can be tuned up and down by demographics. So maybe there is still an argument against everyone doing it.
Many of those cancers are not harmful or would be killed ok their own. And the cost of diagnosis on the patient is not free either. It causes lots of anxiety and stress which also cause large negative health effects too. Over diagnosis is real and also bad. Medical stuff is just really hard
There’s a major difference between having insurance cover something (socialized cost, immediately drives up provider fees for bizarre reasons) and letting the market allow people to buy it themselves (individual cost, the market drives the cost down fast and hard). Notice the pattern with LASIK and GLP1 where lack of insurance coverage has counterintuitively made it cheaper and more accessible.
Let everyone who wants to pay get their scans! But don’t make me pay for you
It seems like the key missing piece is long-term randomized data showing mortality benefit and cost-effectiveness in average-risk populations
Can one solution be always doing two scans, N months apart, before drawing any conclusions (excluding things that can be reliably detected from a single scan)? Initial scan could affect N (if you find something potentially aggressive, you can schedule the second scan sooner). And then do a follow up every M years.
That should exclude benign or very slowing growing things
Extremely anecdotal: my dad’s lung cancer was found incidentally - shoulder pain → shoulder MRI → radiologist noticed lung nodules. The shoulder pain was unrelated, but the scan itself was clinically indicated and there were prior scans to compare against, which made it immediately suspicious and triggered follow-up imaging.
He was also in a higher-risk group (age + history), which in hindsight probably made the incidental finding meaningful rather than noise.
So cases like his make me think less “scan everyone periodically” and more “imaging can be very valuable once risk is non-trivial or there’s a baseline to compare to”. For the general population you’d mostly generate false positives, but for higher-risk groups (older, smokers, prior findings) it seems much more defensible.
Sorry to hear about your dad.
Wrt the issue at hand: yes the cancer was found as an incidental finding on a scan performed for another indication (shoulder pain) -> the question remains whether your father benefitted from finding the cancer. This is seldomly the case.
Anecdotally, everything is possible but on a population scale, actual survival benefit is rare - whereas suffering from the downsides is not - even if only counting unnecessary healthcare cost and time wasted.
In my dad’s case it very likely did - it was lung cancer and still pre-symptomatic, but had already started to metastasize, so a later discovery would probably have meant a much worse prognosis category.
I agree anecdotes don’t generalize and broad population screening sounds like a bad tradeoff. What I’m wondering about instead is risk-stratified situations: once someone already has elevated risk or prior lung disease and you’re imaging them periodically for legitimate reasons, incidental findings may carry much more signal than noise.
For example, people with prior tuberculosis often get periodic chest X-rays, not to screen the general population, but because their baseline risk is different. My dad had prior lung disease and existing imaging to compare against, which probably made the finding actionable rather than just another false positive.
So not “scan everyone”, more “the usefulness of incidental findings rises quickly once pre-test probability isn’t tiny”.
Just to point out, cancer isn't the only reason to get these. Aneurisms, hemachromatosis, etc can all be serious. I know someone who got scanned for $500 and they caught hemachromatosis via iron deposits in the liver. Much better than eventual chirrosis and liver failure.
A blood test is a far cheaper way to check this.
No it isn't.
If you get the MRI you are performing simultaneous blind tests for a thousand rare, unsuspected conditions. The blood test only tests for one of them, and eats 10ml of blood. There isn't enough blood in your body for all those tests.
We should arguably be, in an ideal healthcare system, getting annual MRIs with the other typical tests in a physical, and feeding that data into an AI, and have the AI issue recommendations for informed hazard & secondary testing/biopsy priorities. Tomographic analysis and differential diagnosis is exactly the sort of multidimensional pattern recognition task an AI is great at compared to a human doctor, if you can provide the training data.
Normalizing an annual MRI is the biomedical equivalent to survey astronomy and opening up those gargantuan datasets - you expect lots of simultaneous serendipitous discoveries in unrelated areas without securing an organizational mandate to fund a dedicated research effort into each one of them. The worst the process is ever going to be diagnostically is right now before we're collecting any data in a concerted fashion - every bit of training improves it.
> The blood test only tests for one of them, and eats 10ml of blood. There isn't enough blood in your body for all those tests.
There is some irony here. Getting some blood out is what will cure that iron overload.
"There is some irony here. Getting some blood out is what will cure that iron overload."
The real irony here is that you think treating an undiagnosed condition is a bonus. The patient could just as likely be suffering from anemia...
A blood test doesn't scan for other issues. A genetic test and iron study is going to run a few hundred dollars. Add in the cumulative cost for the other conditions checked for, like aneurism, and a $500 MRI isn't that bad.
What's the base rate of hemachromatosis in the population and what's the false positive rate for MRI detection of the condition?
MRI does not diagnose hemachromatosis. It detects iron deposits (could be due to other harmful issues). To my knowledge it would not produce a false positive. Hemachromatosis is the most common genetic issue in white people, so pretty common (I'm too lazy to look up stats).
I much prefer tests with low false positive rates.
I recently had such a cancer-related test. A cousin had a BRCA2 mutation and I was concerned I could have it also. Insurance would not pay for the testing, but one can get a panel of such genetic tests for just $250 now, so I went ahead. And it was negative. This is reassuring not just to me, but also to my children, and (somewhat) my sibling (the relevant parent is no longer alive).
Had this test been positive, the chance of pancreatic cancer would have gone way up, so frequent scans (I think annual MRI and ultrasound?) would have been justified.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding
Call me naïve but why don't we just update our definition of "(ab)normal" then?
People often contain features in their body that look abnormal on an MRI but might not actually be issues. The issue is that an MRI doesn’t give enough information to know otherwise. This is why they are typically not used in a routine exam by mainstream medicine.
It’s like running ‘ls -la’ on a directory to determine if there are any issues with a piece of software. It could show things that are really bad. It could show things that look weird. But it won’t conclusively debug the code.
1. collecting baseline info for later comparison is good
2. i can afford the money for the chance of early detection. Many cancers are symptomatic only in the latter stages. It does not hurt to check.
I don't see the point of testing constantly. It's just creating stress and probably most of the time, the tumor might be benign or it might be small and go away on its own.
And anyway, you have to die of something so for me cancer would just be a sign that time's up.
> The tests range from several hundred to several thousand dollars, depending on which sections of the body are scanned, and are not covered by insurance.
Even ignoring the overdiagnosing problem (I don't understand how they can determine from MRI when a cancer is a cancer; there are also benign growth and often when they are a certain size, people notice them, but how would MRI help here? Too small areas could be classified as malign; any further procedures can be dangerous - see that Dawson Creek actor recently, the cost of clinical intervention did not help), I think that medicine is increasingly becoming a "only affordable for those who have money". You can see this with regards to gene therapy too - if we ignore the success ratio, many of these therapies are impossible to acquire for Average Joe. Granted, the prices will go down for various reasons (we saw this with Moore's law and many other inventions too), but at the end of the day I feel we are stepping closer and closer to a very unfair society model - more and more superrich, but prices also go up immensely for average people. That model is not sustainable; people will be angry since this is not fair.
Link for users outside of US: https://archive.ph/7qWCf
if you are getting an MRI for some acute condition, I wonder what the marginal cost to 'upgrade' to a 'full body scan' is?
Frankly, this sounds like some people aren't so comfortable with the sheer cost of the machine than their absolute utility. CT and MRI scan machines are something that said to cost like $1m/yr/unit that's ~$500 uninsured/$100 insured per run in Japan that China don't publish data on numbers or distributions of. That says "military grade expensive" written all over.
Any numbers on practical pricing per country for these scans?
is it necessary?
[dead]
Doctors absolutely hate the idea of people being checked for diseases. Every time someone comes out with a plan to detect cancer or prevent HIV, they start screeching.
“But what if the person would have died anyway without noticing they had cancer? Think of the shareholders. They would have paid for treatment for nothing”