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Blood test that finds 50 types of cancer is accurate enough to be rolled out

theguardian.com

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Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#291

Post by exdsq »

iNane9000 wrote: post #266
TaupeRanger wrote: post #218

Earlier quoted context omitted.

You are assigning beliefs to me that I do not hold. As I said, we would need a solid randomized controlled clinical trial to determine whether any particular intervention actually helps patients live longer and/or better. That's the only way we know. So go ahead and collect data, do an RCT, and let us know how it goes.

The problem with this and the nnt gatekeeping is that personalized medicine will always require stepping away from massive double blind randomized placebo controlled multiple meta study levels of evidence. From a patient perspective it feels a lot like economics largely determine medical outcomes.

If you look into QALYs it does - at least in terms of policy over healthcare choices

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#292

Post by exdsq »

throwawaynotmd wrote: post #160
TaupeRanger wrote: post #133

Earlier quoted context omitted.

Lots of problematic assumptions in your reply. >If finding something that otherwise carries no symptoms is best left untreated, then the fact that you found it should make no difference to the decision. The doctor should say that the best course of action is to do nothing. More information can never be harmful. Absolutely and demonstratively false. There is an entire field of health policy that destroys this harmful…

> Many times the patient will push them for further tests and treatment (or the doctors will advocate for it to ease the mind of the patient) which leads to potential harm from unnecessary treatments. > People will ask to be treated anyway, and iatrogenics will rear its ugly head. I just want to say that you are in agreement with my position here. Your point about psychological problems is interesting, but as long as…

Your point about a protectionist racket doesn't hold for countries in the EU which have the same rules around research data and patients

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#293

Post by moralestapia »

nevinera wrote: post #159

0.5% false positive rate is actually quite high. I don't have the numbers, but I'd be surprised if more than 1% of the people that would receive such a screening actually already have cancer , which would mean that it produces about as many false positives as false negatives. Picture a population of a million people, all receiving the test. 1% of them have cancer (unknown to them) - half of those people get a negativ…

I feel it's a net win anyway, if the procedure is not invasive and cheap, you could take one every so often (yearly?) and if something shows up you just double check with a better method or w/e. Better than nothing, which is the current alternative.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#294

Post by AlexCoventry »

amelius wrote: post #277
AlexCoventry wrote: post #259

Earlier quoted context omitted.

If we optimistically assume the claimed 0.5% false positive rate is accurate, and all of the US got tested annually, that's 1.64M false positives per year. Cancer.gov is telling me that approximately 1.8M USians were expected to get cancer last year. That's a positive predictive value of 52%. That still seems highly informative, to me; much higher than the PPV for mammography according to this (admittedly old) study:…

Isn't this exactly why the headline reads "blood test good enough to be rolled out"? I.e., higher FP rate, and it wouldn't be rolled out.

IIRC, the actual article says they're going to do a large trial, with 150k people, and someone in the article expresses skepticism that the estimated FP rate of 0.5% is accurate, because so far it was tested in people where there's some evidence of cancer.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#295

Post by soheil »

TaupeRanger wrote: post #96
reacharavindh wrote: post #3

This is one of those medical revolutions that I am waiting dearly for. Facilities that are not hospitals(to avoid the risk of occupying medical devices that sick people need) built to _regulary_ check up otherwise healthy people for preventive care. Heck, I have so many alerts defined on my monitoring setup for servers to watch for signals of failure before they get too big. But, my own body is not observed until som…

Actually you don't want this, and you are describing a nightmare scenario that everyone who studies health policy understands all too well. Mass screening of healthy people will result in extreme iatrogenics and unnecessary psychological damage and stress (which leads to physical effects as well), not to mention overwhelming the medical system. The fact is that many things that could be detected will never result in…

I wonder if the equivalent of extreme iatrogenics and unnecessary psychological damage and stress also occurs when monitoring servers too much. I have a feeling it does. This is why I typically set higher thresholds like more disk space, memory (equivalent of exercise and healthy diet?) that I really need so I stop monitoring my servers religiously.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#296

Post by LightMachine »

TaupeRanger wrote: post #96
reacharavindh wrote: post #3

This is one of those medical revolutions that I am waiting dearly for. Facilities that are not hospitals(to avoid the risk of occupying medical devices that sick people need) built to _regulary_ check up otherwise healthy people for preventive care. Heck, I have so many alerts defined on my monitoring setup for servers to watch for signals of failure before they get too big. But, my own body is not observed until som…

Actually you don't want this, and you are describing a nightmare scenario that everyone who studies health policy understands all too well. Mass screening of healthy people will result in extreme iatrogenics and unnecessary psychological damage and stress (which leads to physical effects as well), not to mention overwhelming the medical system. The fact is that many things that could be detected will never result in…

This mindset kills more people than Hitler. Have a good day.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#297

Post by yazaddaruvala »

jacquesm wrote: post #84
petra wrote: post #81

Earlier quoted context omitted.

>> treatments are not necessarily an improvement over having a mostly dormant cancer. This is true today. But if we could detect cancer at a really early stage, relatively reliably, maybe this means we could develop new and effective treatments that are low risk and low on side-effects ? And if we had that, early cancer detection will also have a totally different meaning, so that could help with the mental health as…

We could develop those treatments irrespective of early detection, there are plenty of examples of early detection of cancers today to make that feasible, this does not depend on a new test regime.

You may know more than me about medicine, but when it comes to allocating resources, I know just as much if not more than you.

If we start to test more, and understand the magnitude of the problem better (despite false positives/negatives) we can better allocate capital to solving this problem.

Sure, "cancer is horrible, we should already allocate as much capital as possible" but this just isn't reality. As soon as the addressable market for early-detected cancer treatment goes from X per year to 100X per year (and 1,000X or 10,000X is "even better"), big pharma has more motivation to actually R&D safe treatments for early-detected cancers.

Not testing more to detect cancer early is silly, if only from the perspective of capital allocation.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#298

Post by grahamburger »

TaupeRanger wrote: post #267
throwawaynotmd wrote: post #258

Earlier quoted context omitted.

I should say, if you know ex ante that certain results are not worth acting on, then when you actually get those results ex post, you should ignore them just the same. So actually running a test cannot formally be the problem.

That is not how medicine works, especially with cancer. Very often we simply don't know whether or not to "ignore" something. But the harms of knowing are not zero, and therefore screening can itself be a net negative. That's why a well powered RCT is required to say whether it benefits patients or not.

Isn't the only way to learn what things we can ignore and what things we can't ignore to do a lot more testing? Is there a better way to learn that? It seems like having a lot more data from tests is the kind of thing that would have some short term harm but massive long term benefits.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#299

Post by ericd »

rackjack wrote: post #252
tnel77 wrote: post #244

Earlier quoted context omitted.

>Getting a cancer diagnosis is a "huge deal" because getting cancer is one of the worst experiences a human can go through. I’ve never been given a cancer diagnosis, but I’d imagine it’s much, much worse to be told you have stage 4 cancer versus stage 1. As the other person stated, the culture would adapt and people would learn to not immediately sell their house and go on a Vegas bender just because a yearly prevent…

> I’ve never been given a cancer diagnosis, but I’d imagine it’s much, much worse to be told you have stage 4 cancer versus stage 1. It's bad all the way. > If you are one of the people with a false positive, you schedule a follow-up and move on accordingly. People already do schedule follow-ups and additional tests and second opinions when they get a positive. > Your position is anti-progress just for the sake of be…

My impression is that yours is the consensus view in the medical community. But I think that what all these people are telling you is that they'd much rather have a much higher chance of a false positive stage 1 diagnosis than even a much lower chance of false negative diagnosis until they're at stage 4. And any positive result from this would obviously be couched in a doctor consult saying "if you have cancer, which this test doesn't definitively show, it's still very early, we're just going to keep an eye on it, we didn't get any confirmation from a chest x-ray or CT", etc

And having a memento mori can be a positive thing.

Re: Blood test that finds 50 types of cancer is accurate enough to be rolled out

#300

Post by [deleted] »

rackjack wrote: post #252
tnel77 wrote: post #244

Earlier quoted context omitted.

>Getting a cancer diagnosis is a "huge deal" because getting cancer is one of the worst experiences a human can go through. I’ve never been given a cancer diagnosis, but I’d imagine it’s much, much worse to be told you have stage 4 cancer versus stage 1. As the other person stated, the culture would adapt and people would learn to not immediately sell their house and go on a Vegas bender just because a yearly prevent…

> I’ve never been given a cancer diagnosis, but I’d imagine it’s much, much worse to be told you have stage 4 cancer versus stage 1. It's bad all the way. > If you are one of the people with a false positive, you schedule a follow-up and move on accordingly. People already do schedule follow-ups and additional tests and second opinions when they get a positive. > Your position is anti-progress just for the sake of be…

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