
New blood test could detect more than 20 types of cancer - spking
https://www.telegraph.co.uk/news/2019/09/28/new-blood-test-could-detect-20-types-cancer/
======
_ihaque
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...](https://ihaque.org/posts/2019/07/02/early-detection-
mid-2019-part-1/)

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...](https://ihaque.org/posts/2019/07/08/early-detection-
mid-2019-part-2/)

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...](https://ihaque.org/posts/2019/08/18/early-detection-
mid-2019-part-3/)

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

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ethhics
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...](https://www.wcrf.org/dietandcancer/cancer-
trends/worldwide-cancer-data)

~~~
sandworm101
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.

~~~
killjoywashere
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?

~~~
jessriedel
> 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.

Newbie question: wouldn't a test with very few false positives, but frequent
false negatives, still be good for screening if it was cheaper/easier than
existing screening, so it could be given to more of the population based on a
weaker suspicion threshold? Like, in the limit of it being free and having
zero false-positive rate, you'd give it to everyone.

(Maybe given your expertise it's obvious to you that the test is sufficiently
expensive that this argument doesn't apply?)

~~~
ac29
Frequent false negatives mean it will miss many people who do have the
disease, leading them to believe they are healthy until the disease progresses
to a point it may be more difficult to treat.

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doctoring
In addition to the press release someone posted, if you’re interested in some
of the (high level) science behind this, I’d encourage you to read the ESMO
presentation slides this news comes from: [https://grail.com/wp-
content/uploads/ESMO_2019_Oxnard_CCGA2_...](https://grail.com/wp-
content/uploads/ESMO_2019_Oxnard_CCGA2_Training_Final.pdf)

I don’t think the article mentions it, but the study is funded by Grail, which
is commercializing a variety of related technologies.

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petilon
Original press release that is the basis for the story: [https://www.dana-
farber.org/newsroom/news-releases/2019/new-...](https://www.dana-
farber.org/newsroom/news-releases/2019/new-blood-test-capable-of-detecting-
multiple-types-of-cancer/)

------
kaikai
A pathologist friend told me “there’s a good chance you already have the
cancer that might eventually kill you.” The danger of early detection of
cancer is that we’ll end up treating fat more people than we would otherwise,
and cancer treatment is often brutal. I’ll be interested to see what better
detection actually does for mortality rates.

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cheschire
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.

~~~
cwkoss
I was thinking about it in terms of cataloguing the foods you eat for later
analysis, but could work for this too.

Would it be possible to make portable device that could freeze dry a drop of
liquid? Heat pumps and pressure vessels both get much simpler with smaller
sizes.

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Gatsky
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.

~~~
dannykwells
...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.

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aszantu
no mentioning of false positives

~~~
PhantomGremlin
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._

~~~
kurthr
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.

~~~
sandworm101
It isnt 20 tests. It is one test regime that detects the presence of 20
diseases. It doesnt diagnose any one disease, just red-flags patients for more
accurate testing.

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nerder92
Elizabeth Holmes seals of approval.

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ganitarashid
Theranos?

