New blood test could detect more than 20 types of cancer • Hacker News Board

Re: New blood test could detect more than 20 types of cancer

#21

Post by _ihaque » Sun, Sep 29, 2019, 8:50 PM UTC

The results Grail presented as a talk at ESMO are fairly similar to those they presented in somewhat less detail at conferences earlier in the year (AACR and ASCO).

For those who are interested in a deeper dive on this technology, its potential limitations, and its potential benefits, I wrote up a three-part series earlier this year breaking down recent advances in liquid-biopsy-based cancer detection:

Part I: regarding tumor fraction (this goes into depth about the stage I limitations noted by other commenters) https://ihaque.org/posts/2019/07/02/early-detection-mid-2019...

Part II: technical advances from Grail (the authors here) and Guardant (one of their main commercial competitors) https://ihaque.org/posts/2019/07/08/early-detection-mid-2019...

Part III: clinical performance and economics - integrating the sensitivity and specificity numbers with a simple model for important clinical parameters like adherence (how many people prescribed to take the test actually do), and cost: https://ihaque.org/posts/2019/08/18/early-detection-mid-2019...

Disclaimer: I'm the former CSO of a competing company, but I no longer work in this space.

Re: New blood test could detect more than 20 types of cancer

#22

Post by cheschire » Sun, Sep 29, 2019, 9:20 PM UTC

One day I hope that I will have a device that can digitize my blood sample at home so that remote cloud processing can warn me of issues. Life can sometimes get in the way of preventative checks. Social anxiety might be a part of that too.

Re: New blood test could detect more than 20 types of cancer

#23

Post by Gatsky » Sun, Sep 29, 2019, 9:49 PM UTC

This is very promising. The performance will definitely get better, this is like the first smoky pictures coming out of an MRI.

The real challenge is going to be dealing with the result... it isn’t simply a matter of continuing to use the same treatments we do now but applied to earlier stage disease.

Re: New blood test could detect more than 20 types of cancer

#24

Post by chiefalchemist » Sun, Sep 29, 2019, 10:13 PM UTC

bobwaycott wrote: post #18

chiefalchemist wrote: post #14

Earlier quoted context omitted.

How so they determine false negatives? Are there other less broad and more expensive test? That said, isn't it also possible at Stage 1 for the body to cure itself? That is, __in theory__ is it possible Stage 1 defecation is too early? That med intervention could be premature?

I think you meant detection —and not defecation —right?

Yeah. Oops. Autocorrect FTL

Re: New blood test could detect more than 20 types of cancer

#25

Post by [deleted] » Sun, Sep 29, 2019, 10:16 PM UTC

Gatsky wrote: post #23

This is very promising. The performance will definitely get better, this is like the first smoky pictures coming out of an MRI. The real challenge is going to be dealing with the result... it isn’t simply a matter of continuing to use the same treatments we do now but applied to earlier stage disease.

[deleted]

Re: New blood test could detect more than 20 types of cancer

#26

Post by snagglegaggle » Sun, Sep 29, 2019, 10:22 PM UTC

sandworm101 wrote: post #17

nugget wrote: post #15

Earlier quoted context omitted.

Many of these early cancers are asymptomatic and universal diagnostic imaging in the absence of symptoms is cost prohibitive. Better blood tests address that and other important gaps.

If you start testing asymptomatic people, healthy people, even a 1% false positive rate is tricky.

But if the tests are cheap enough you can repeat them and compare. Bringing cost of blood diagnostics down is I think a good idea. I have fitness and health conscious friends who regularly get direct-to-consumer tests as a matter of course. In a few cases they have caught issues very early.

This is understanding there are some false positives, but being able to recognize them and learn to ignore them is better than not testing out of fear you overreact.

Re: New blood test could detect more than 20 types of cancer

#27

Post by killjoywashere » Sun, Sep 29, 2019, 10:32 PM UTC

sandworm101 wrote: post #10

ethhics wrote: post #9

From [0], the types of cancer they can screen make up at least 81.4% of new cancer diagnoses, which means that with their 99.4% true positive rate, this test should be able to correctly identify ~80% of new cancer incidences. If I'm doing my math right, that's really impressive. [0]: https://www.wcrf.org/dietandcancer/cancer-trends/worldwide-c...

It seems to have a great false positive rate, but a not-good false negative rate. It misses the bulk of stage one cancers. So its utility for early diagnosis (the important bit) is marginal at this time.

For those not in the lab business: a low false positive rate and a high false negative rate are useful for confirmatory testing, not for screening. Such tests are terrible for screening. So this might be able to insert itself between the screening test (e.g. mammo, psa, or CXR) and the biopsy, but it won't replace the biopsy because you still have to characterize the cancer for further treatment decisions.

From a market positioning standpoint, it's not bad, because you don't piss off the generalist physicians by stealing their screening role, and you don't piss off the pathologists or surgeons by stealing their biopsies. The question is, does it add sufficient value for the payer to pay?

Re: New blood test could detect more than 20 types of cancer

#28

Post by dannykwells » Mon, Sep 30, 2019, 12:13 AM UTC

Gatsky wrote: post #23

This is very promising. The performance will definitely get better, this is like the first smoky pictures coming out of an MRI. The real challenge is going to be dealing with the result... it isn’t simply a matter of continuing to use the same treatments we do now but applied to earlier stage disease.

...Actually, it is. Survival when using the same treatments is much higher in earlier stage patents is much better than in later stage. Full stop. Of course not everyone will be cured, but this will make a big dent.

Re: New blood test could detect more than 20 types of cancer

#29

Post by dannykwells » Mon, Sep 30, 2019, 12:14 AM UTC

kurthr wrote: post #7

PhantomGremlin wrote: post #4

Earlier quoted context omitted.

It does mention this, but doesn't use those exact two words: Crucially, 99.4 per cent cases identified as cancer were correctly spotted - meaning just 0.6 per cent of cases were misdiagnoses of healthy patients.

By the birthday paradox, that means 11% of healthy people will be misdiagnosed for one form of cancer on the 20 test panel. That's going to require some in person discussion and review... maybe they can handle that with the NHS, but I think the US patient would end up spending an extra $1000+ due to required human contact, beyond any test cost.

The 99.4% specificity is presence of cancer, not by organ. Nice try though.

Re: New blood test could detect more than 20 types of cancer

#30

Post by sandworm101 » Mon, Sep 30, 2019, 12:39 AM UTC

snagglegaggle wrote: post #26

sandworm101 wrote: post #17

Earlier quoted context omitted.

If you start testing asymptomatic people, healthy people, even a 1% false positive rate is tricky.

But if the tests are cheap enough you can repeat them and compare. Bringing cost of blood diagnostics down is I think a good idea. I have fitness and health conscious friends who regularly get direct-to-consumer tests as a matter of course. In a few cases they have caught issues very early. This is understanding there are some false positives, but being able to recognize them and learn to ignore them is better than n…

Repeating a test doesnt help. The blood result likely wont be different the second time. A false negative is a person for whome the test just doesnt work, no matter how many times you repeat it. (In reality, these sorts of important tests are run multiple times against the single sample before they print the results.)