> 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?
How often do full-body MRIs find cancer?
201–210 of 290 posts
Re: How often do full-body MRIs find cancer?
#202Earlier quoted context omitted.
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.
Re: How often do full-body MRIs find cancer?
#203Earlier quoted context omitted.
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.
> 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 y…
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.
Re: How often do full-body MRIs find cancer?
#204One 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 peop…
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.
Re: How often do full-body MRIs find cancer?
#205Arguments 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…
> 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 anal…
> 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.
Re: How often do full-body MRIs find cancer?
#206Arguments 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…
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.
Re: How often do full-body MRIs find cancer?
#207Earlier quoted context omitted.
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.
Harmful to shareholder value. Personally I’d rather have cancer checked out rather than have a “wait and die” approach
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."
Re: How often do full-body MRIs find cancer?
#208Arguments 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…
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.
Re: How often do full-body MRIs find cancer?
#209Doctors 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…
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
"First, do no harm."
Re: How often do full-body MRIs find cancer?
#210Arguments 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 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…
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.