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One whole-body MRI could replace multiple cancer scans

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Re: One whole-body MRI could replace multiple cancer scans

#131

Post by nathan_f77 »

nknealk wrote: post #13

Many doctors hate full body scans. Every individual has a handful of anomalies which are almost always benign. They show up on full body scans and chasing them down comes with cost and patient risk. I have a hard time with reporting like this that doesn't quantify cost of biopsy on false-positives as well as cost of complications from examining false-positives. Source: worked in clinical research for 2 years.

What about having regular full body scans and tracking any anomalies over a period of months or years? You could safely ignore anything that doesn't change, but you would immediately spot any fast growing cancers before it's too late.

Re: One whole-body MRI could replace multiple cancer scans

#132

Post by mattkrause »

abecedarius wrote: post #121
mattkrause wrote: post #114

Earlier quoted context omitted.

We could do an autopsy on you right now if you want. How sure are you that you just stubbed your toe and it's not some highly metastasized cancer?

"Of course it can be less than the cost of the test." includes non-monetary costs. I thought this was clear since the benefit we're talking about is obviously not wholly monetary. (Or even mostly.)

I suppose you're right that the expected value of information, not including the acquisition costs, is never negative.

That feels like cheating though--this information isn't free.

My argument is that the expected value of this information, including acquisition costs, can very easily be negative, since you can't just "ignore" being dead. These costs are extremely large in my snarky autopsy suggestion, but dominate for whole-body MRIs + followups too. The catch is that the scan doesn't have huge benefits and the costs of the followups, while non-trivial, aren't exactly open-heart surgery either, so both are in the neighborhood of zero, except for the monetary expense, which will be crazy high.

Re: One whole-body MRI could replace multiple cancer scans

#133

Post by cameronbrown »

petschge wrote: post #55
chongli wrote: post #23

Earlier quoted context omitted.

This sounds to me like doing a full workup on blood chemistry. Individuals vary so much that you can get false positives. Wouldn't it be more useful as a baseline? Scan once and store it, then scan every few years and compare. If any of the "anomalies" has grown or new ones have appeared between scans, then they might be worth a second look?

Getting a baseline is harder than it sounds. In the case of blood chemistry that is caused by fluctuations due to time of day, time of month, season, what you recently ate and so one. In the case of MRI the problem is that internal organs shift to the point that it is impossible to automatically compare. And a experienced doctor comparing the scan millimeter for millimeter takes hours and would be very expensive. Eve…

> internal organs shift to the point that it is impossible to automatically compare.

Seems like a good area to apply machine learning if we had enough data?

Re: One whole-body MRI could replace multiple cancer scans

#134

Post by tellak »

rolleiflex wrote: post #67
nknealk wrote: post #13

Many doctors hate full body scans. Every individual has a handful of anomalies which are almost always benign. They show up on full body scans and chasing them down comes with cost and patient risk. I have a hard time with reporting like this that doesn't quantify cost of biopsy on false-positives as well as cost of complications from examining false-positives. Source: worked in clinical research for 2 years.

A decent portion of my family are MDs. This is accurate. However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we…

I am actually an MD.

> Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree

How, pray tell, are we actually determining which are malignant and which are not?? I’ll give you a hint: the charitable explanation is you are completely ignorant, the less charitable one is that you consider Mengele and Ishii modern medicine heroes. And that is even if the determination by imaging alone is even possible.

Once again I have to point out on HN... not everyone in the medical world is an idiot incapable of analytical thinking, it is just that a lot of us care about ethics. Our patients, even in research, are more than just numbers.

Re: One whole-body MRI could replace multiple cancer scans

#135

Post by stcredzero »

mattkrause wrote: post #112
rolleiflex wrote: post #67

Earlier quoted context omitted.

A decent portion of my family are MDs. This is accurate. However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we…

You're understating the costs. Determining whether something is (non) malignant isn't trivial. It often requires a more invasive test (e.g., biopsy, exploratory surgery). We try to avoid those procedures not just because we're cheap or afraid, but because they have a real risk of harming us 'squishy humans'. For example, detecting prostate cancer a few months earlier is often not a huge win on its own. It is even les…

You're understating the costs.

I think you're correct in the current context. However, this strikes me as a sign of some kind of paradigm shift waiting to happen, enabled by the reduced cost of data gathering, data processing, and improvements in AI.

There was a time when many things which are mass produced now were once handcrafted luxury items. Perhaps, as technology improves, it will one day be cost effective to take a whole body scan into account. I can imagine a day when an AI would digest the information from a full body scan, then autonomously plan robot keyhole surgery to take many of the biopsies.

It's certainly possible that more data would eventually let us avoid most invasive followups, that's nowhere near certain.

I think it's likely to happen in decades, if our civilization doesn't fall soon.

Re: One whole-body MRI could replace multiple cancer scans

#136

Post by jlpom »

MRI are generaly considered safe but my personnal experience contradict this. I passed a 3T brain MRI (with gadolinium injection for angiography) ~80 days ago and my life has been seriously painful since then. I have experienced hypertension (often >170 of systole, seem unrelated but never had high tension of my life and like the rest of theses issues it appeared exactly after the MRI), sleep issues, head difficulties to think and head "rigidity", sexual/erectile disfunction (other side-effets started to dim a bit since then, but not this one), continuous heat on of my face up to 3 weeks after the exam. I am not trying to spread FUD but this has unfortunately been my experience. I'm a fragile kind of person, though I didn't expected it would be (so) unsettling. YMMV but you may reconsider passing one if you don't have confidence it would help you diagnosis or find issues (stenosis, neoplasm...).

Re: One whole-body MRI could replace multiple cancer scans

#137

Post by refurb »

jlpom wrote: post #136

MRI are generaly considered safe but my personnal experience contradict this. I passed a 3T brain MRI (with gadolinium injection for angiography) ~80 days ago and my life has been seriously painful since then. I have experienced hypertension (often >170 of systole, seem unrelated but never had high tension of my life and like the rest of theses issues it appeared exactly after the MRI), sleep issues, head difficultie…

Reaction to the contrast agent?

Re: One whole-body MRI could replace multiple cancer scans

#138

Post by abecedarius »

mattkrause wrote: post #132
abecedarius wrote: post #121

Earlier quoted context omitted.

"Of course it can be less than the cost of the test." includes non-monetary costs. I thought this was clear since the benefit we're talking about is obviously not wholly monetary. (Or even mostly.)

I suppose you're right that the expected value of information, not including the acquisition costs, is never negative. That feels like cheating though--this information isn't free. My argument is that the expected value of this information, including acquisition costs, can very easily be negative, since you can't just "ignore" being dead. These costs are extremely large in my snarky autopsy suggestion, but dominate f…

Yup, agreed! In fact I wouldn't have done the test mentioned above if I'd been better informed (an MRI with gadolinium contrast; I was only told the latter bit the day I showed up for it. There seems to be a bit of controversy about possible low-level health effects of this contrast agent, and considering I was very probably fine a priori, I think it was a mistake to do this. But it's kind of another thing to decide this on the spot after making an appointment.)

(To say nothing of the extra $1000 surprise bill...)

Anyway, what is raising my hackles doesn't seem rational in the same way. It seems to have the flavor of "when we look and see certain signs, our system too often takes stupid harmful costly actions on that information. Therefore, don't look!" It'd be reassuring to continue "This is a workaround to an admittedly irrational system while we have the following people researching better ways to improve." But that's not the sort of thing I've read.

Re: One whole-body MRI could replace multiple cancer scans

#139

Post by tellak »

Brakenshire wrote: post #126
louden wrote: post #118

Earlier quoted context omitted.

More data is not always better. The collection process itself can be dangerous or unpleasant for the patient. Several years ago I worked on a study looking at the spread of bacterial lung infections in long term hospital patient. In order to get the data, we would have to intubate patients that did not need it. In this case, the people who approve these studies rightfully ruled that getting that data would be too pai…

> The collection process itself can be dangerous or unpleasant for the patient. That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous. > Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregat…

> That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous.

With him classifying all MDs as idiots, no it is not asinine.

I’ve known few academic physicians that would turn down data if it can be ethically obtained.

The difference between the medical profession and, say Google, is that we as a general rule do not consider the populace one big lab to experiment on as we please. The consequences are more than a little different.

It’s not like things were always this way in medicine either.

Re: One whole-body MRI could replace multiple cancer scans

#140

Post by koboll »

mattkrause wrote: post #112
rolleiflex wrote: post #67

Earlier quoted context omitted.

A decent portion of my family are MDs. This is accurate. However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we…

You're understating the costs. Determining whether something is (non) malignant isn't trivial. It often requires a more invasive test (e.g., biopsy, exploratory surgery). We try to avoid those procedures not just because we're cheap or afraid, but because they have a real risk of harming us 'squishy humans'. For example, detecting prostate cancer a few months earlier is often not a huge win on its own. It is even les…

It's nice that you think those are costs worth remaining ignorant over. However, when the ignorance is about things that literally might kill me, my personal opinion is that it's worth it.
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