Cheap blood test detects pancreatic cancer before it spreads
30 comments
·February 13, 2025bloomingkales
jghn
There is an enormous gulf between what Theranos was doing and these sorts of tests. For starters, one was just making crap up. The other actually has some potential merit.
duxup
So for a test like this, do you just give it to everyone without symptoms?
For a very high mortality cancer is it even useful to test after you have reason to test?
I read about these tests and breakthroughs that involve general predictions and test, but I'm pretty sure when I go into the doctor I'm not screened proactively for all that much.
ethbr1
The intent of non-invasive tests like this are that you give them to everyone, at scale, frequently.
And specifically tune them to minimize false negatives.
Worst case with a false positive? You're causing someone anxiety and giving them an extra scan.
Best case? You just saved someone's life by detecting an aggressive cancer early enough to do something about it.
At the end of the day aggressive, metastatic cancer is a time game. If the cancer is given time, it becomes progressively harder and harder to treat, and effective treatment options become tougher on the rest of the body, until finally there's nothing to be done.
So anything that gains time is critical.
jghn
> Worst case with a false positive? You're causing someone anxiety and giving them an extra scan.
It is arguable that this as minor an issue as you make it out to be. There has been work to try to assess this (google "cancer overdiagnosis").
The counterargument to what you state is that a false positive can not only lead to stress & unnecessary/more invasive screening, but a treatment plan that's a net negative. For instance: if a cancer were detected and it'd wind up being a cancer that someone dies with instead of from, and the treatment causes worse outcome than the cancer itself, that's not good. The hard issue here is that these things need to be determined at a population scale, and one can always cherry pick personal anecdotes in either direction to tug at heartstrings.
We seem to have found ourselves at a point where it's clear there's a balance that needs to be struck, but it's unclear what that balance is yet.
nsxwolf
Worst case is the scan “sees something” which then puts them on a diagnostic anxiety roller coaster for the rest of their lives, “just to be safe”. When in the alternate universe they might not have gone another 60 years hardly ever seeing a doctor.
giantg2
They generally aren't going to give them to everyone. They will give them to everyone within a certain group, such as age 30+ since the under 30 group is very low risk (unless family history, etc). Similar to how they don't test most kids and younger people for cholesterol - it's just not a significant problem for that age group.
ethbr1
Traditionally, tests have been metered that way because of costs (expensive reagents, preparation, processing) or side effects (radiation from scans).
But the actual relevant equation is {cost of testing} vs {cost of delayed treatment}
If the cost of testing, in economic and health senses, decreases while the cost of delayed treatment holds constant, a different mass deployment optimal point is created.
Thankfully broader proactive testing is also in insurance companies' financial interests, given the high costs of late stage cancer treatment.
jillesvangurp
Depends, colon cancer, breast cancer, prostrate cancer, etc. are pretty commonly tested/screened for in certain age groups and that definitely saves lives.
My aunt died of pancreatic cancer last year. It's a pretty common and aggressive form of cancer. She only had a few months from diagnosis to the grave. By the time she got diagnosed, there was nothing that they could do except provide pain relief.
chasebank
Isn't this fundamentally a statistical issue? With a test sensitivity of 99%, meaning a 1% false positive rate, administering it universally to individuals would generate a significant number of false positives. This influx could overwhelm the system, potentially limiting access for those who genuinely require medical attention.
crhulls
Sensitivity is the false negative rate.
Although it is the opposite of what the doctors want, I would prefer a less sensitive but highly specific test.
If I had 80% sensitivity I'd miss out on 20% of cancers, but if I could match that with a 99.9% specificity I'd have very few false positives.
I hope this type of test can tune that direction.
thinkingtoilet
If the test is cheap, you could run it 2 or 3 times. Then the false positive rate would be pretty low and you could proceed with more intense treatments/diagnostics.
onlyrealcuzzo
Isn't this problem fixed by just doing another blood test?
I thought that's how HIV rapid testing works.
duxup
That's what I'm wondering too. Even if 1%, if the follow up is very expensive, the initial test might be cheap but overall cost might be very expensive / prohibitive.
allturtles
AFAIU, with pancreatic cancer usually by the time you have symptoms you are already stage 4 and uncurable. So I'm assuming the intent is to test non-symptomatic people.
duxup
That's what I was assuming as well. But then that leads to my other question, do we really regularly screen people this proactively for much at all?
mwigdahl
In the US, asymptomatic people 50+ are routinely screened for colon cancer with a much more expensive and invasive process. A cheap blood test for another major killer seems pretty reasonable to add in.
The_Colonel
Measuring your blood pressure is an example of proactive screening.
I assume we will start screening for things like cancer when the test will be as simple / cheap as measuring your blood pressure.
mbreese
Here is the link to the actual paper.
pfdietz
> The nanosensor correctly identified healthy individuals 98% of the time,
Since pancreatic cancer would have to be detected before any symptoms occur for this to be useful, the test would have to be applied to everyone. The incidence of PC is 1 per 10,000 per year. If the test is applied once per year, then for every true positive result there would be 200 false positives (actually worse, since it only detects PC 3/4 of the time.)
newsclues
If you can cheaply test everyone, and narrow down the number of people requiring more expensive testing, you can potentially, at scale, detect and limit negative health outcomes. There is both an economic and societal benefit to testing and treating people.
pfdietz
If the more expensive testing is at all invasive (for example, biopsies) or still has false positives (benign tumors, say) then it could end up being a net negative. This effect has bedeviled screening for other cancers, like breast and prostate cancers.
aszantu
[flagged]
infecto
Thats for the summary. This is huge if proven true. The problem with many of the cancer tests historically is their high false positive rate.
allturtles
Isn't this still too high of a false positive rate to be useful? IIUC, if you give this to 100,000 people, it will give you 2,000 false positive results. But only 13.5 new pancreatic cancer cases occur per 100,000 adults in the U.S. each year [0]. So if you took this test annually, a positive result still means a less than 1% chance you have cancer?
[0]: https://seer.cancer.gov/statfacts/html/pancreas.html
edit: although that NCI data doesn't make sense to me. If only 13.5 new cases appear per 100K, how can that accumulate to lifetime diagnosis rate of 1.7%? 100000 * 0.017 = 1700; 1700 / 13.5 = ~126 years to accumulate a 1.7% chance of diagnosis.
lr4444lr
You wouldn't just screen the entire population with this test. You'd give it to the high risk factor subpopulations where the rate is way higher than 13.5%: older people, tobacco users, etc.
duxup
I wonder what the follow up test is like / cost. If it is highly accurate, but you end up doing expensive follow up tests for 2,000 people ... that has to factor into the overall "cost" of such screening right?
null
Elizabeth Holmes: I was too early!
Speaking of the banality of evil in another thread, Elizabeth Holmes really just made a poorly timed stock pick. Lying and stuff, that’s a constant amongst that type, so let’s factor that out.
She might have been right all along though, weird.