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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

#81

Post by petra »

jacquesm wrote: post #66
pieno wrote: post #63

Earlier quoted context omitted.

It seems like you and GP are agreeing on the fact that right now we don’t do too many preventive checks because the cost of testing is higher than the benefits (mainly because false positives could lead to risky and invasive follow-up testing to confirm that it’s indeed a /false/ positive; and knowing that you have something sooner rather than later may not meaningfully affect the outcome of the disease; and costs of…

Even 100% true positive rate would not guarantee improved patient outcomes with massive testing. This is grounded in a poor understanding of what improved patient outcomes are all about, which is fine with me but to see this so misunderstood is a bit disappointing. Better tests do not automatically lead to better outcomes. They will lead to many more cancers detected, and they will lead to more interventions. Just on…

>> 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 aspect too.

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

#82

Post by jacquesm »

bijant wrote: post #79
jacquesm wrote: post #56

Earlier quoted context omitted.

Your belief has no representation in medical science, which is mostly evidence based. A lot of data has been collected on this, studies (many) have been conducted and the general consensus is that more testing absent symptoms does not lead to improved patient outcomes. That you want to have some kind of theoretical argument in the face of this evidence might be interesting to you but it isn't to me.

You’re correct in that this is a prevailing view in epidemiological/Public Health circles. But Medical Science is not only the macro but also the micro level perspective. Individual Practitioners of medicine might well appreciate more and earlier Data. A first principals based argument is a complementary approach that might uncover things that an empirical view might hide.A good example of this is the Australian Nobl…

Absolutely, on an individual basis is where the difference can be made and this is exactly why it is important if you are tested positive for some cancer to work together with your oncologist to ensure the best possible outcome for you. The interesting thing here is that laypeople tend to be in favor of massive testing and almost always want to be operated on/have chemotherapy/have radiation therapy even if that is not necessarily the best path for them.

This leads to lots of suffering and hardship.

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

#83

Post by jacquesm »

sweetdreamerit wrote: post #78
jacquesm wrote: post #56

Earlier quoted context omitted.

Your belief has no representation in medical science, which is mostly evidence based. A lot of data has been collected on this, studies (many) have been conducted and the general consensus is that more testing absent symptoms does not lead to improved patient outcomes. That you want to have some kind of theoretical argument in the face of this evidence might be interesting to you but it isn't to me.

Your point is interesting. Can you cite some literature that supports it?

See below, there are quite literally 100's of studies supporting this so it should not be difficult to find many more articles about this.

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

#84

Post by jacquesm »

petra wrote: post #81
jacquesm wrote: post #66

Earlier quoted context omitted.

Even 100% true positive rate would not guarantee improved patient outcomes with massive testing. This is grounded in a poor understanding of what improved patient outcomes are all about, which is fine with me but to see this so misunderstood is a bit disappointing. Better tests do not automatically lead to better outcomes. They will lead to many more cancers detected, and they will lead to more interventions. Just on…

>> 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.

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

#85

Post by 11thEarlOfMar »

jacquesm wrote: post #74
11thEarlOfMar wrote: post #70

Earlier quoted context omitted.

I see it more in the vein of vaccinations. A preventive care activity, not as a reaction to a symptom. Speaking only for myself, I am regularly screened, asymptomatically, for skin, prostate and colon cancers. That screening is a non-event for me because I grew up knowing that we will get screened on a regular basis for these cancers. With additional asymptomatic testing, there will be false positives. Re-test using…

With the present invasive methods of excising cancer the answer is that on an individual basis you might be better off with early detection but on a statistical basis across a larger population you'll be worse off. The important variables are patient age, how aggressive the cancer is (growth rate), what the risks of that particular type of cancer metastasizing are, what your genetic disposition is etc.

Again, personally, I lost both parents to cancer. One thyroid (very slow progression) one pancreatic (very fast). In both cases, I believe that pre-symptomatic detection would have had a high probability of eradicating their cancers. That experience skews my view and if I get the opportunity, I'll have these tests done 3x annually.

But I understand your point. How about making it elective? That way, people who prefer to not endure the risk of false positives or the anxiety of awaiting the test results can opt out.

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

#86

Post by jacquesm »

dannyw wrote: post #21
Gatsky wrote: post #15

Earlier quoted context omitted.

Note this test is about early detection, not prevention. If your pancreatic cancer is detected early, you will still need to have your insides rearranged to get it out.

That's a critically better health outcome though. It's like fixing a corruption bug when you detect it on one server, versus finding out there's corruption in every shard and all of your backups.

> That's a critically better health outcome though.

Not necessarily. It depends on how old you are, what your genetic make-up is, whether the cancer is growing rapidly, whether it has easy access to other organs to spread to (or has already begun to do so) and so on. It's not a binary thing.

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

#87

Post by plank_time »

jacquesm wrote: post #80
iandanforth wrote: post #76

Earlier quoted context omitted.

I detest this mindset. It is incredibly counter productive. "Our tests are bad, so lets not test" is not a thought worthy of respect. This states that you know about a problem but want to continue to ignore that problem. Reprehensible. No, we should take the exact opposite approach. Test everyone constantly until such methods become both cheap and powerful. So yeah we all have some cancer load but if the diagnostic o…

The problem is not my mindset, but your understanding of the subject material. Patient outcomes have very little to do with the quality of the tests, even a 100% accurate test would not necessarily lead to improved patient outcomes because these are defined independent of the tests. You are treating this like a software problem, but it isn't, it's a medical problem, and medical problems tend to be complex because the…

This is an absolutely absurd thing to say.

“We’ve never had blood tests that detect pancreatic cancer early, therefore we should never use them because when we used other means to try to detect early, it didn’t lead to better outcomes.”

If you can detect colon, kidney pancreatic or liver cancer early, you might be able to do surgery or develop treatments at the stage 1 stage. Right now we don’t have anything except MRIs and CT scans that are too hard and expensive to do frequently. And if you are diagnose with pancreatic cancer it’s usually so late that you will basically die in weeks.

You’re basically saying “give up. Even if we detect early you all die anyway” which is frankly stupid. You’re discounting the possibility that early detection by means of a blood test adds whole new layers of possibilities to fight those particularly dangerous cancers.

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

#88

Post by mritchie712 »

londons_explore wrote: post #31

More technologies like this are coming... Is it worth taking blood samples now, keeping them in a freezer, and then waiting for the test tech to come so I can get it tested to see disease progression of whatever disease I get when I get older?

yes, having mysterious blood in your freezer is a good conversation starter for guests too. Bonus points if you get creative with the labels for each sample.

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

#89

Post by jacquesm »

plank_time wrote: post #87
jacquesm wrote: post #80

Earlier quoted context omitted.

The problem is not my mindset, but your understanding of the subject material. Patient outcomes have very little to do with the quality of the tests, even a 100% accurate test would not necessarily lead to improved patient outcomes because these are defined independent of the tests. You are treating this like a software problem, but it isn't, it's a medical problem, and medical problems tend to be complex because the…

This is an absolutely absurd thing to say. “We’ve never had blood tests that detect pancreatic cancer early, therefore we should never use them because when we used other means to try to detect early, it didn’t lead to better outcomes.” If you can detect colon, kidney pancreatic or liver cancer early, you might be able to do surgery or develop treatments at the stage 1 stage. Right now we don’t have anything except M…

But: that surgery is not without risk, and if there are no symptoms there is a fair chance that there never will be symptoms. Depending on your age and your genetic make-up you might be more or less at risk. There is such a thing as spontaneous remission and so on.

So no, I'm not 'basically giving up', and no you won't die anyway (well, unless you take that in the most abstract way), in particular likely not from cancer.

Even for those cancers where we do screen (such as for instance breast cancer) it is not a given that the increased frequency of detection has led to better patient outcomes.

But once you know someone's genetic disposition increased frequency of testing might be advantageous.

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

#90

Post by mrtnmcc »

jacquesm wrote: post #62
dmitryminkovsky wrote: post #60

Earlier quoted context omitted.

Not just that, but neither GP nor anyone else in this thread seems to be mentioning the mental health implications of constantly screening for life threatening diseases. For me, and many others I am sure, this would be bad . My quality of life would suffer tremendously, to the point of likely substantial loss of mental function. And I am definitely not one of these “we all die someday” types. Far from it. It’s just t…

Yes, that's a very important point. Even regular checks for cervical cancer or breast cancer can be a huge stress factor, especially in the period just prior to the test and in the waiting period until the results are in, and even more so if the test yields a false positive.

Is the problem not so much the testing, but that most current treatments for cancers are so crude? If you have a relatively asymptomatic cancer, the treatments (chemo, surgery, proton beams) and psychological stress of discovery could be worse (statistically) than letting the body naturally take care of it. This probably depends very much on the cancer ( e.g., some Thyroid cancers might be better left alone).

If our best treatment for fixing a harddrive was to hit it with a hammer, then maybe we'd also conclude monitoring for minor bit errors in data centers is unwise too.

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