Blood test that finds 50 types of cancer is accurate enough to be rolled out • Hacker News Board

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

#231

Post by jacquesm » Fri, Jun 25, 2021, 3:56 PM UTC

Silhouette wrote: post #227

jacquesm wrote: post #204

Earlier quoted context omitted.

Yes, they can, but not in a blanket fashion where a test with a relatively high false positive rate and a relatively low sensitivity (between 18 and 50% for this particular test) is released without patient outcomes as the main driver of whether or not to apply the test absent further symptoms. Whether this test is one that can serve in that particular role is definitely not something that has already been determined…

Well, yes, it's only worth running a screening programme if you have a usefully accurate test and if you can then make some useful intervention after a positive result. Is anyone here disagreeing with that, though? Maybe we interpreted OP's comment that you quoted differently? I read it as being in favour of preventative medicine as a whole, not necessarily endorsing this specific test at this specific point in time.…

That certainly isn't the goal, it is strictly meant within the context as established by the root comment. To present this at the present time as a revolutionary breakthrough and to suggest using this test in particular for mass screening is not a path that will lead to a good outcome unless a lot more data is gathered to support that position.

The people that have built this are at the forefront of this field, I've been following them for quite a while - since the announcement in March last year - it has direct bearing on some other things that I'm involved with and I'm hopeful that it will at first be a useful diagnostic tool and that in a later stage - after the kinks have been worked out and there is sufficient data - that it might help with more than that.

Preventative medicine obviously has its place and for selected cancers we are now in a phase where early detection leads to improved outcomes. But we should continue to be weary of overselling this - the same has already happened with other cancer tests.

Absent symptoms mass testing has serious risks and these will obviously be taken into account when setting policy, the article is actually reasonably neutral in this respect so I wonder why it leads to an immediate response that is equating this with a medical revolution. It may well be, but there is no evidence right now that this is the case.

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

#232

Post by msrenee » Fri, Jun 25, 2021, 3:56 PM UTC

reacharavindh wrote: post #7

zrail wrote: post #5

Earlier quoted context omitted.

That's already a thing, at least everywhere I've ever lived. You have a primary care doctor, you see them at least once a year, they do a physical exam, maybe some blood work. This test maybe becomes standard of care for everyone annually.

May be I have been living in a bubble. I remember doing a “annual check up” in the US about 5 years ago, and that was super basic - blood pressure, sugar, cholesterol levels etc. they didn’t even do a detailed enough bloodwork to test for allergies. Definitely not looking for any disease vectors. Now, I live in DK, and my visit to the GP would always go with my hard attempts to convince my GP that something is really…

I don't think blood tests for allergies are a regular thing anywhere. It's generally done if you can't have the skin testing and the skin testing is something you go to a specialist for. It's not something that's screened for regularly.

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

#233

Post by TaupeRanger » Fri, Jun 25, 2021, 3:58 PM UTC

plank_time wrote: post #211

rackjack wrote: post #184

Earlier quoted context omitted.

> It correctly identified when cancer was present in 51.5% of cases, across all stages of the disease, and wrongly detected cancer in only 0.5% of cases. If all 300 million Americans get blood tested each year, that is 1 and a half MILLION people who are falsely told they have CANCER. One and a half MILLION people whose life gets turned upside down, WRONGLY, due to a blood test -- at least, until they take a second o…

Do you think that technology doesn’t improve over time? You are suffering from a fixed mindset, where you think people or technology is as good as it gets now and never improve. You should read up more on growth mindsets. People and technology aren’t fixed. They change and improve over time. If people had your attitude about AIDS we would have let all AIDS patients die because “oh well nothing we can do.” Luckily tho…

You are clearly confusing treatment with diagnosis/screening and should consider walking away from the conversation until you get a better understanding of the ideas being discussed here. Right now you're adding a lot of unnecessary noise with bad arguments.

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

#234

Post by horstmeyer » Fri, Jun 25, 2021, 4:00 PM UTC

moooo99 wrote: post #67

horstmeyer wrote: post #45

Earlier quoted context omitted.

Same for me in Germany. You are eligible to one checkup when you turn 35, that's it, lol. Otherwise you have to convince the doctor a certain check is necessary. Usually doctors don't like that very much. I would even happily pay for it myself, but I still need to convince the doctor I'm not a hypochondriac.

Thats not true. The cost of the checkup are covered once before you turn 35 and every three years for anybody above the age of 35 [1]. Still, people have to be willing to do that checkup, make an appointment by themselves and so on. Still, seeing what is and what isn't covered by public health insurance just seems so stupid. The focus on cure instead of prevention, and that not even particularly good. It's sad to see…

Thanks for the correction, that was what my doctor told me. But maybe I also misunderstood him.

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

#235

Post by fortran77 » Fri, Jun 25, 2021, 4:02 PM UTC

plank_time wrote: post #128

TaupeRanger wrote: post #96

Earlier quoted context omitted.

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…

Utterly wrong. You are conflating current technology like MRIs and CT scans that only detect lumps, to blood tests that detect CANCER. Yes, if every lump were treated and excised then it would be problematic. But CANCER is different. The only cancer that you might be able to leave alone is prostate because it grows so slowly. Everything else is a risk. And if we can treat cancer at early stage 1, then maybe people wo…

My father died from metastasized prostate cancer.

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

#236

Post by fortran77 » Fri, Jun 25, 2021, 4:04 PM UTC

plank_time wrote: post #147

TaupeRanger wrote: post #138

Earlier quoted context omitted.

You say "utterly wrong" and yet you clearly have no idea what you're talking about and have never even approached the field of health policy. Screening has to PROVE that it makes people live longer or better, just like any other intervention. It is not the case that screening is automatically good, otherwise we would be giving 20 year olds colonoscopies. Just because you find something, doesn't mean you've helped the…

We don’t give colonoscopies to 20 years olds because it’s an expensive, invasive test with a low rate of cancer. We don’t give mammograms to under 40 year olds these days because the same and it’s notoriously inaccurate. We give blood glucose level tests and cholesterol tests to everyone every year at the physical because they are cheap and easy to administer. Even though the effects of both may take decades to have…

My father died from metastasized prostate cancer.

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

#237

Post by gradys » Fri, Jun 25, 2021, 4:05 PM UTC

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…

There's an interesting discussion raging on elsewhere in the thread about the possibility for cultural adaptation that would enable us to cope with statements like "the cancer test was positive, but there's still a decent chance you don't have cancer".

There's also an interesting question, taking your roughly 1:1 true to false positive ratio as an example, of whether the marginal true positive does more good for the world than the marginal false positive.

Side-stepping those questions though, they probably won't give this test to literally every person in the population. How much does the picture improve when you give this only to people over 50? Or only smokers? You could still massively increase effective screening for cancer with a cheap and easy test if you combine it with enough population filtering to increase the true positive/false positive ratio to something like 70-90% rather than the 50%

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

#238

Post by rackjack » Fri, Jun 25, 2021, 4:06 PM UTC

function_seven wrote: post #216

rackjack wrote: post #190

Earlier quoted context omitted.

Same vibe as "I would just simply..." What do you think the entire medical, pharmaceutical, bioinformatic, etc. industries have been doing for decades? Are you really so arrogant to think that other people are too lazy and stupid to think of your brilliant idea and that you are simply more intelligent than everybody else? Do you really think people haven't been trying?

If they aren't mass collecting this data in the first place (for the reasons outlined above), then how can they be doing this? Or, if they are doing this from quality samples of the population, then we have data to show that, for example, "Yes, Mr. Function Seven, your scan shows elevated levels of Widget-5a enzymes. This is often a precursor to Gadget Cancer, but 30% of the population shows this elevation, while onl…

They are mass collecting the data. They have more data than they know what to do with. Bioinformatics abuses data science at levels comparable to Google and Facebook.

They are getting quality samples from the population. But it's not a simple as "high enzyme = maybe good chance of cancer". How are you going to get those enzymes from their blood in a way that can be applied to the general population? Before that, how do you know there's not confounding factors (of which they are a LOT)?

> So either we have this data and we can give accurate advice, or we don't have this data because we're afraid of over-diagnosing non-problems.

It's not that easy.

Look at this pathway: https://www.pathwaycommons.org/guide/workflows/rna_seq_to_en...

From here: https://www.pathwaycommons.org/guide/workflows/rna_seq_to_en...

This is what people think the activation of genes is. What they THINK the activation of genes is.

Note the following:

- They don't know all the genes. They are constantly identifying new ones. The number of gene pathways people are pretty sure are complete is small. I don't know if this one is one of the "pretty sure" ones.

- Gene pathways are not just complex in terms of size, they are also non-linear. This is not a computer program, this is a horrible biological mess where biological components constantly and probabilistically emit chemicals.

I don't even think that the pathway I gave you is super representative - it doesn't feature the ridiculous non-linearity and uncertainty that many pathways at the bleeding edge have. They can get much worse.

People are not burying their heads in the sand. They are trying their almighty to dig up from bedrock and reach the sky.

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

#239

Post by andai » Fri, Jun 25, 2021, 4:07 PM UTC

dmitryminkovsky wrote: post #65

One of my great fears in life is that employers/insurers will impose this en masse on people, causing immeasurable harm to the mental health of people who can’t handle the anxiety that this type of approach to medicine would cause. I’m definitely a big proponent of evidence-based medicine and using it to help living quality life as long as possible, but this sort of thing would just wreck my day to day existence and…

Do you mean the psychological impact of the screenings, constantly wondering if you have cancer, if the test missed anything etc, rather than fear of the procedure itself?

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

#240

Post by plank_time » Fri, Jun 25, 2021, 4:08 PM UTC

TaupeRanger wrote: post #233

plank_time wrote: post #211

Earlier quoted context omitted.

Do you think that technology doesn’t improve over time? You are suffering from a fixed mindset, where you think people or technology is as good as it gets now and never improve. You should read up more on growth mindsets. People and technology aren’t fixed. They change and improve over time. If people had your attitude about AIDS we would have let all AIDS patients die because “oh well nothing we can do.” Luckily tho…

You are clearly confusing treatment with diagnosis/screening and should consider walking away from the conversation until you get a better understanding of the ideas being discussed here. Right now you're adding a lot of unnecessary noise with bad arguments.

Nope. You are confidently wrong again.

Early diagnosis means new ways of treating cancers like liver and pancreatic. You don’t seem to understand this. Right now there is practically no treatments for either because it’s detected so late. Maybe after 20 years of early diagnosis we can treat pancreatic cancer the same way we do others.

Let me guess. You were telling people in early 2020 that N95 masks don’t work.