15 ms·

How often do full-body MRIs find cancer?

162 points by brandonb 8mo ago

lucb1e 8mo ago
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.
- jml78 8mo ago
  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.
  - codethief 8mo ago
    > 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?
    - jml78 8mo ago
      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.
      - colletta 8mo ago
        [dead]
- majorchord 8mo ago
  > 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?
  - p0pularopinion 8mo ago
    > 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.
    - bookofjoe 8mo ago
      >"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/ https://pubmed.ncbi.nlm.nih.gov/33360667/
  - sxg 8mo ago
    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.
  - alexey-salmin 8mo ago
    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.
- paulpauper 8mo ago
  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
  - Snoozus 8mo ago
    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.
joezydeco 8mo ago
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?
- johndhi 8mo ago
  Er wait is retinal cancer a thing?
  - lbreakjai 8mo ago
    Yes. Like OP, I do a picture every year. Three years ago there was a scare, that turned out to be nothing.
  - butvacuum 8mo ago
    theres a ton of degeneative stuff too that's not strongly age corrilated.
  - p0pularopinion 8mo ago
    Yes. You can also have melanoma on your uvea
  - driggs 8mo ago
    Retinal imaging is used to detect damage from glaucoma or other eye disease, by "diffing" the fine blood vessels and nerves.
  - joezydeco 8mo ago
    Family history of glaucoma and macular degeneration. Also had a semi detached retina when I was a kid.
- butvacuum 8mo ago
  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.
dmitrygr 8mo ago
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.
jmward01 8mo ago
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).
- p0pularopinion 8mo ago
  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.
  - cyberax 8mo ago
    "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.
    - tptacek 8mo ago
      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.
      - lostlogin 8mo ago
        This is pretty much what the experts say: https://www.ranzcr.com/college/document-library/2024-position-statement-on-whole-body-mri https://www.ranzcr.com/college/document-library/2024-positio...
monero-xmr 8mo ago
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
mmaunder 8mo ago
“ 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.
- rembal 8mo ago
  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.
  - p0pularopinion 8mo ago
    > 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
    - mcbain 8mo ago
      I have multiple scans a year. "Scanxiety" is real.
      - lostlogin 8mo ago
        Multiple PETs?
giantg2 8mo ago
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.
- tptacek 8mo ago
  What's the base rate of hemachromatosis in the population and what's the false positive rate for MRI detection of the condition?
  - giantg2 8mo ago
    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).
- lostlogin 8mo ago
  A blood test is a far cheaper way to check this.
  - mapt 8mo ago
    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.
mgraczyk 8mo ago
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.
- lich_king 8mo ago
  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.
  - mgraczyk 8mo ago
    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
    - lich_king 8mo ago
      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.
jamesbelchamber 8mo ago
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.
- cogman10 8mo ago
  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.
  - jamesbelchamber 8mo ago
    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 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 :)).
  - randallsquared 8mo ago
    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.
NedF 8mo ago
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jongjong 8mo ago
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.
hoc 8mo ago
Any numbers on practical pricing per country for these scans?
tsoukase 8mo ago
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.
- AYBABTME 8mo ago
  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.
  - deleted 8mo ago
    [deleted]
  - cheschire 8mo ago
    “slightly infantilizing” might be an appropriate course given how well LLM sycophancy works on the general populace.
Nevermark 8mo ago
> 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.
- mtoner23 8mo ago
  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
rich_sasha 8mo ago
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?
- foota 8mo ago
  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.
- maho 8mo ago
  > 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.
- IshKebab 8mo ago
  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 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.
numpad0 8mo ago
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.
tspng 8mo ago
Link for users outside of US: https://archive.ph/7qWCf https://archive.ph/7qWCf
nayroclade 8mo ago
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.
- kcexn 8mo ago
  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?
  - MagicMoonlight 8mo ago
    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”
    - JackFr 8mo ago
      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.
srdjanr 8mo ago
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
MagicMoonlight 8mo ago
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”
RataNova 8mo ago
It seems like the key missing piece is long-term randomized data showing mortality benefit and cost-effectiveness in average-risk populations
shevy-java 8mo ago
> 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.
pfdietz 8mo ago
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.
the_monocle 8mo ago
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.
- doRadiology 8mo ago
  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.
  - the_monocle 8mo ago
    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”.
johnnyfeng 8mo ago
is it necessary?
jdthedisciple 8mo ago
> 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?
- kube-system 8mo ago
  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.
gorfian_robot 8mo ago
if you are getting an MRI for some acute condition, I wonder what the marginal cost to 'upgrade' to a 'full body scan' is?
smsm42 8mo ago
This article's numbers are (not) surprisingly useless. So, for 1.8% of people in one study who did MRI they found cancer. Is it a lot? A few? I mean, how many people do these MRIs, out of general population? Are those high-risk people or just random people (or, maybe, only rich people?) and what their base rate incidence of cancer? What is base rate incidence of cancer in general population and how often those cancers are discovered by non-MRI tests? If I had to decide whether or not MRI is worth it for cancer detection - this is what the article is supposed to be about? - those are the questions I'd ask. None of them are addressed in the article. I think if we dropped everything in it but the last sentence, it would lose nothing of substance: > No matter what you decide for yourself, consult a licensed medical professional for advice.

162 points by brandonb 8mo ago

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.

jml78 8mo ago
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.
- codethief 8mo ago
  > 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?
  - jml78 8mo ago
    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.
    - colletta 8mo ago
      [dead]
majorchord 8mo ago
> 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?
- p0pularopinion 8mo ago
  > 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.
  - bookofjoe 8mo ago
    >"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/ https://pubmed.ncbi.nlm.nih.gov/33360667/
- sxg 8mo ago
  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.
- alexey-salmin 8mo ago
  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.
paulpauper 8mo ago
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
- Snoozus 8mo ago
  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.

joezydeco 8mo ago

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?

johndhi 8mo ago
Er wait is retinal cancer a thing?
- lbreakjai 8mo ago
  Yes. Like OP, I do a picture every year. Three years ago there was a scare, that turned out to be nothing.
- butvacuum 8mo ago
  theres a ton of degeneative stuff too that's not strongly age corrilated.
- p0pularopinion 8mo ago
  Yes. You can also have melanoma on your uvea
- driggs 8mo ago
  Retinal imaging is used to detect damage from glaucoma or other eye disease, by "diffing" the fine blood vessels and nerves.
- joezydeco 8mo ago
  Family history of glaucoma and macular degeneration. Also had a semi detached retina when I was a kid.
butvacuum 8mo ago
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.

dmitrygr 8mo ago

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.

jmward01 8mo ago

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).

p0pularopinion 8mo ago
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.
- cyberax 8mo ago
  "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.
  - tptacek 8mo ago
    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.
    - lostlogin 8mo ago
      This is pretty much what the experts say: https://www.ranzcr.com/college/document-library/2024-position-statement-on-whole-body-mri https://www.ranzcr.com/college/document-library/2024-positio...

monero-xmr 8mo ago

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

mmaunder 8mo ago

“ 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.

rembal 8mo ago
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.
- p0pularopinion 8mo ago
  > 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
  - mcbain 8mo ago
    I have multiple scans a year. "Scanxiety" is real.
    - lostlogin 8mo ago
      Multiple PETs?

giantg2 8mo ago

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.

tptacek 8mo ago
What's the base rate of hemachromatosis in the population and what's the false positive rate for MRI detection of the condition?
- giantg2 8mo ago
  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).
lostlogin 8mo ago
A blood test is a far cheaper way to check this.
- mapt 8mo ago
  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.

mgraczyk 8mo ago

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.

lich_king 8mo ago
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.
- mgraczyk 8mo ago
  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
  - lich_king 8mo ago
    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.

jamesbelchamber 8mo ago

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.

cogman10 8mo ago
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.
- jamesbelchamber 8mo ago
  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 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 :)).
- randallsquared 8mo ago
  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.

NedF 8mo ago

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jongjong 8mo ago

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.

hoc 8mo ago

Any numbers on practical pricing per country for these scans?

tsoukase 8mo ago

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.

AYBABTME 8mo ago
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.
- deleted 8mo ago
  [deleted]
- cheschire 8mo ago
  “slightly infantilizing” might be an appropriate course given how well LLM sycophancy works on the general populace.

Nevermark 8mo ago

> 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.

mtoner23 8mo ago
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

rich_sasha 8mo ago

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?

foota 8mo ago
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.
maho 8mo ago
> 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.
IshKebab 8mo ago
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 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.

numpad0 8mo ago

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.

tspng 8mo ago

Link for users outside of US: https://archive.ph/7qWCf https://archive.ph/7qWCf

nayroclade 8mo ago

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.

kcexn 8mo ago
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?
- MagicMoonlight 8mo ago
  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”
  - JackFr 8mo ago
    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.

srdjanr 8mo ago

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

MagicMoonlight 8mo ago

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”

RataNova 8mo ago

It seems like the key missing piece is long-term randomized data showing mortality benefit and cost-effectiveness in average-risk populations

shevy-java 8mo ago

> 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.

pfdietz 8mo ago

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.

the_monocle 8mo ago

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.

doRadiology 8mo ago
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.
- the_monocle 8mo ago
  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”.

johnnyfeng 8mo ago

is it necessary?

jdthedisciple 8mo ago

> 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?

kube-system 8mo ago
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.

gorfian_robot 8mo ago

if you are getting an MRI for some acute condition, I wonder what the marginal cost to 'upgrade' to a 'full body scan' is?

smsm42 8mo ago

This article's numbers are (not) surprisingly useless. So, for 1.8% of people in one study who did MRI they found cancer. Is it a lot? A few? I mean, how many people do these MRIs, out of general population? Are those high-risk people or just random people (or, maybe, only rich people?) and what their base rate incidence of cancer? What is base rate incidence of cancer in general population and how often those cancers are discovered by non-MRI tests? If I had to decide whether or not MRI is worth it for cancer detection - this is what the article is supposed to be about? - those are the questions I'd ask. None of them are addressed in the article. I think if we dropped everything in it but the last sentence, it would lose nothing of substance: > No matter what you decide for yourself, consult a licensed medical professional for advice.