25 ms·

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

630 points by kieranmaine 5y ago

noway421 5y ago
Elizabeth Holmes would be proud
reacharavindh 5y ago
This is one of those medical revolutions that I am waiting dearly for. Facilities that are not hospitals(to avoid the risk of occupying medical devices that sick people need) built to _regulary_ check up otherwise healthy people for preventive care. Heck, I have so many alerts defined on my monitoring setup for servers to watch for signals of failure before they get too big. But, my own body is not observed until something bad needs treatment. Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! All the advancement in technology in recent years, this ought to happen sooner than later.
- zrail 5y ago
  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.
  - reacharavindh 5y ago
    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 wrong and I am not a crazy lunatic who is simply looking for attention. Although, I have never directly asked for a checkup(while being healthy) to look for disease vectors. I’ll ask and see what they say. I’d prefer if this is outside of the general healthcare system though. I don’t want to occupy Doctors, and medical labs from people who are actually sick _now_ and need those tests, and attention.
    - flemhans 5y ago
      Another Danish person here, your GP would never check you in any sort of fashion here, unless you already have (serious) symptoms.
    - horstmeyer 5y ago
      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.
      - moooo99 5y ago
        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 how much money goes to waste for useless treatments with something like homeopathy while people who really need proper treatment are stuck with the cheapest option that is paid for. [1] https://www.bundesgesundheitsministerium.de/checkup.html https://www.bundesgesundheitsministerium.de/checkup.html (German)
        horstmeyer 5y ago
        Thanks for the correction, that was what my doctor told me. But maybe I also misunderstood him.
    - refurb 5y ago
      This approach actually works really well for conserving healthcare dollars. If a doctor feels like nothing is wrong, 99% of the time they’ll be right. Sucks to be that 1% where you die of a cancer that would have been caught, but that’s the trade off. The marginal return of each dollars spent on screening goes down quickly. At a population level you can’t justify it, but at a personal level you can.
  - vmception 5y ago
    That’s not good enough for cancer because we dont even know how fast or slow it grows. Even if it cancer cells multiplied at the rate of a fetus that would be too fast for an annual physical. Congratulations, death. Ideally something like a wearable computer or nanomachines in your blood stream automatically report anomalies for individualized treatment.
    - danuker 5y ago
      > Even if cancer cells multiplied at the rate of a fetus I suspect at least some cancers multiply slower than that, because they work against the rest of the cells.
    - dryrun 5y ago
      Given the amount of "I don't want bill gates injecting me a tracker!", I have some idea of how a conversation with the same people about nano machines in their body would go. I would also bet on the time-frame between this and the availability of your data on the servers of your health insurance.
      - vmception 5y ago
        Not my problem, human cancers stay in there own bodies and are not communicable To our knowledge
        jacquesm 5y ago
        Not normally, no. But there are some puzzling exceptions: https://www.discovermagazine.com/health/the-cancers-that-are-contagious https://www.discovermagazine.com/health/the-cancers-that-are...
        vmception 5y ago
        These are all in animals and I specified human cancers for that specific reason, thanks for the article though, I only knew about the Tasmanian Devil one
  - Clampower 5y ago
    This is not true in the Netherlands. You don’t get any tests if there is nothing wrong. Healthcare in this country scares me.
    - pelorat 5y ago
      You can ask for a blood test though and ask that they check specific markers. But I agree that huisartsen are too dismissive in general.
      - egeozcan 5y ago
        Same in Germany (Hausärzte). Even if you have a specific complaint, you'll just be told to go home and drink a lot of water. They just don't have the capacity to test for causes. I'm not sure if I can even pay someone to make extensive tests here. Never tried. Perhaps one needs to go to the US for that.
    - the-dude 5y ago
      Take control. Regular doctors in NL are basically there to prevent you from getting care. Say you want a blood test, and what for. I they don't cooperate, move to the next doctor.
    - danuker 5y ago
      In the US, the medical system was (and might still be) the top third cause of death, of which 5/6ths were due to medicine side-effects. https://nutritionfacts.org/video/how-doctors-responded-to-being-named-a-leading-killer/ https://nutritionfacts.org/video/how-doctors-responded-to-be... I suspect doctors in the Netherlands are taught not to over-diagnose. Are they paid through national insurance?
      - goodpoint 5y ago
        Yes, the US medical system is a disaster.
    - refurb 5y ago
      Really? Not even a blood pressure check or a physician listening to your lungs or just examine your skin for weird moles? That’s terrible.
  - postingawayonhn 5y ago
    I've never lived anywhere where this was common. The public health system can't afford to fund it and most of the population doesn't want to (or can't afford to) pay for it themselves.
- xwdv 5y ago
  My experience is people don’t really care much about their bodies beyond the aesthetics. Most treat it like a dumpster and ingest whatever crap feels good and hope for the best. Caring too much makes you some sort of health freak in their eyes, with way too much time on your hands.
  - carlmr 5y ago
    I'm not sure this is true. At least in my friend circle most people put a lot of care into their nutrition and fitness. Maybe talk to your friends about it and get them to be healthier?
    - handrous 5y ago
      How do you think we get the rates of diabetes and obesity we have in the US, without that being true for most people in most places and in most social circles? Rich social networks tend to live much healthier lifestyles than average. Normal is fried starch and tens to hundreds of ounces of soda more days than not, and exercise is that maybe you golf sometimes or play in a seasonal company softball league (drinking way more calories than you're burning, almost certainly).
  - danuker 5y ago
    The top risk factors for death confirm what you say, sadly. https://ourworldindata.org/causes-of-death#the-number-of-deaths-by-risk-factor https://ourworldindata.org/causes-of-death#the-number-of-dea...
- sbelskie 5y ago
  A big part of this is the fact that learning information (about a disease or condition) early is often NOT the same thing as learning information that will change a patient’s clinical outcome.
  - radu_floricica 5y ago
    I never understood this. I mean I totally get the concept, but I don't get how it came to influence policy. Put it like this: how many people are you willing to kill to make sure people don't find out they're sick? Because that's what it boils down to. And it sounds... sociopathic.
    - sbelskie 5y ago
      I’m not sure I understand what you mean. It seems like you’re framing my motivation as not wanting people to know that they are sick and being willing to trade peoples lives to achieve that outcome, which I don’t think is at all what my above comment says.
      - radu_floricica 5y ago
        It is how I understood it, sorry about that. What did you mean?
    - dabbledash 5y ago
      The idea is that treatment also has risks and false positives are an issue. If you gave a mammogram to every 20 year old woman, you would end up doing a large number of unnecessary biopsies and you’d find almost no real cancer. In the end, you’d lose more people than you would save. Or that’s the idea. I’m no expert in this but it makes sense to me conceptually.
      - JumpCrisscross 5y ago
        > If you gave a mammogram to every 20 year old woman, you would end up doing a large number of unnecessary biopsies and you’d find almost no real cancer If you gave a mammogram to every 20-year old, you wouldn't do a biopsy when you got a positive. You'd increase monitoring and maybe suggest lifestyle changes. The same way we don't immediately catherize everyone who comes back with high cholesterol.
- Gatsky 5y ago
  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.
  - junon 5y ago
    "Preventative care" refers to the field of medicine called preventative medicine/care/health, which specifically aims at making regular checkups and other monitoring facilities free and accessible in order to improve health via early-detection. Oftentimes, doing these sorts of things lowers your insurance premiums or makes costs lower if something does happen (not always, but sometimes). These sorts of things are also generally free as it costs the insurance company less in the long run if you're doing them frequently enough. Perhaps a bit of a misnomer, but "preventative care" doesn't necessarily mean medicinal prevention of any sort.
  - dannyw 5y ago
    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.
    - carlmr 5y ago
      Ransomware infecting one machine or all machines including backups would also be a good analogy.
    - jacquesm 5y ago
      > 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.
    - Gatsky 5y ago
      I’m not saying it isn’t a great development. It certainly adds an option for early detection of some cancers where there previously were none. But it isn’t cancer prevention. It is a highly sophisticated technical undertaking which for educated and motivated patients in well resourced health systems will reduce cancer mortality and morbidity by some increment. Depending on many factors this could be a big or small increment. In the real world the efficacy will be less than what the trial shows. It is also likely that Grail (with north of $1 billion in VC funding) will charge as much as they can for this test. The size of the trials necessary to prove efficacy means that there will be highly constrained competition in this space. The distinction with prevention is important, because we ultimately must aim for preventing almost all cancers, and not be content with anything less than that. Disclaimer: I’m an Oncologist.
- Tolyzz 5y ago
  Cause things break down all the time. And everything can look like early signs of trouble. There are lot useless docs and surgeons waiting to perform unnecessary expensive procedures much like building contractors. Oh that pipe is leaking let's just replace this entire load bearing wall etc cause we have this new cool machine that can. Second opinions are over rated cause the majority don't care. There is an endless demand for their trade. My dad lost his hearing at 35 after they performed surgery to remove a tumor they detected. They detected the same Tumor in my brother when he was in his 20s and wanted to operate with no guarantee of hearing preservation. He declined. He is going to turn 40 soon and would have most likely been deaf for 20 years if he had gone through with it. Minor issues with his balance but other than that he is fine even though tumor gets tracked every couple years and is still growing.
  - BallyBrain 5y ago
    This sounds like a regulation and education problem to me. early detection doesn't have to mean treatment, it could just be monitoring and change of lifestyle.
- jacquesm 5y ago
  Regularly checking people that are otherwise healthy for cancer will turn up a lot of cancer through false positives or slowly growing ones, will lead to a lot of unnecessary intervention and will in fact lead to a reduction in quality of life and lifespan. This is one of the reasons why exhaustive cancer screening (which was more costly in the past but could have been done) was not promoted, it had nothing to do with ability, but everything to do with outcomes. Those cancers where checkups are useful we already do regular screenings for. For aggressive cancers - the ones that are really problematic - you would have to do such a test too frequently to make any real difference, for instance, if you were to test annually you'd be on average 6 months away from your next test, plenty of time for such a cancer to develop and kill you. So this is not the kind of breakthrough that you may think it is.
  - bruce343434 5y ago
    Who are "we"? I'm certainly not "regularly" screened.
    - jacquesm 5y ago
      That's your choice, assuming you live in a developed country. Assuming the United States see here: https://www.cdc.gov/cancer/dcpc/prevention/screening.htm https://www.cdc.gov/cancer/dcpc/prevention/screening.htm and if elsewhere consult your local CDC equivalent.
      - postingawayonhn 5y ago
        Current screening methods tend to be costly and/or uncomfortable for the person being screened. A simple blood test could lead to higher uptake and more regular screening.
  - tarsinge 5y ago
    > Those cancers where checkups are useful we already do regular screenings for. More like “are <practical given available tests> and useful”. Regarding your last paragraph cancer screening seems very rare except for one or two types (at least where I live), so statistically yes an annual test will miss the worst case you presented, but for the vast majority it will be a huge improvement.
- deleted 5y ago
  [deleted]
- TaupeRanger 5y ago
  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 symptoms or other noticeable problems. Further, for many things that can be detected we can't really do much about, so by detecting it early you are just reducing the amount of life they have left without worrying about their disease, or causing unnecessary treatment (which includes unnecessary damage, cost, stress, etc.)
  - throwawaynotmd 5y ago
    The argument you’re making has always bothered me because it’s hiding the ball. If finding something that otherwise carries no symptoms is best left untreated, then the fact that you found it should make no difference to the decision. The doctor should say that the best course of action is to do nothing. More information can never be harmful. If you know information is best not acted on in the abstract, then you also know you should not act on it in particular. So what you really mean but have left unspoken is one of two things. First, that doctors are untrustworthy people who make recommendations and decisions based on concerns other than their patient’s wellbeing, such as covering their asses from lawsuits or making more money. But rather than fix that, you would rather keep patients more ignorant and away from the doctor in the first place. Which actively harms people who do have honest doctors. That is, your approach of not testing hurts people with honest doctors to protect people with dishonest doctors. Or second, if you take dumb patients as the problem, you are willing to hurt people with good decision making ability (who would heed their good doctor’s advice to leave the possible ailment untreated) so you can protect people with bad decision making. Because many times, these tests will uncover things that obviously need treatment. They will save many lives. But because more stupid people will hurt themselves, then no one should have access to them. The political and moral assumptions built into these positions are immense and yet the medical field tucks those away and pretends that this is just a purely scientific truth, that someone running more harmless tests is actually inherently harmful. That is a lie! And a very nasty one at that.
- hannob 5y ago
  The reason this is not happening isn't a technical one. It's that people with a medical background will tell you this isn't a healthy utopia, it's a nightmare. Medical tests are complicated. They often have significant false positive and false negative rates. Testing people at scale increases the number of people with wrong test results and can cause harm if you start treating people based on wrong test results. The more healthy people you test the more false positives you get. The goal of evidence based medicine is to use tests when they can help. It's not to test as many people as possible. This is reasonable. You want to improve patient's lives. Whether or not a test is improving patient's lives is often not easy to answer and has to consider many things.
  - axxto 5y ago
    The point of this is not that you get a definitive diagnosis; it's just a somewhat reliable marker on whether you may need to be concerned and get more accurate (but more harmful) imaging or invasive tests to rule out something.
    - dangerlibrary 5y ago
      You only need one false positive test result that ends up with a colonoscopy to understand how costly and uncomfortable these errors can be. (I'm using an uncomfortable and illustrative example, but a colonoscopy is honestly pretty safe and boring as invasive clinical diagnostic procedures go)
      - theptip 5y ago
        Perhaps a better example than you intended -- recently colonoscopies are being considered more risky as a regular screening tool, because the procedure itself can result in harms, including (rarely) death. Not an expert here, but it seems they are still used in a fairly wide age group, but the recent trend is to be more cautious about their usage, as particularly for older patients they are more risky vs. the potential benefits. [1] However I think this concern would be reduced if we had better first-line screening like the tests in TFA; the harms come from using a relatively-risky assay like colonoscopy for regular screening in healthy individuals, whereas if we had better noninvasive screening, the colonoscopy could be reserved for patients where there's a higher probability of a positive diagnosis. [1]: https://jamanetwork.com/journals/jama/fullarticle/2529486 https://jamanetwork.com/journals/jama/fullarticle/2529486
- dukeofdoom 5y ago
  One issue is that your body may have all types of tissues that might be precancerous or slow growing cancerous growths that the test will identify. To get to them and remove them would do far more damage than leaving them alone. Even with things like prostate cancer, which is fairly easy to get to. Leaving it alone, is often the right choice depending on the age of the patient and speed of growth of the cancer.
- andai 5y ago
  I expect this won't catch on until it becomes a wearable technology, and then it will catch on overnight.
- DoreenMichele 5y ago
  Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! We can and plenty of people do, usually with tools like health journals and smart watches recording biometrics.
- matheusmoreira 5y ago
  > Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! Maybe one day we'll have cybernetic implants that can constantly monitor our health. Hopefully it won't turn into a privacy nightmare.
xiphias2 5y ago
Galleri test looks great, but it is available only in US and UK. I wish they would allow private patients in other countries to take the test somehow.
Zenst 5y ago
Whole area of having tests that give definitive answers in the field of health is the one area in which it can't get enough of. Biggest issue health wise many have is time from issue to getting a correct diagnoses, whatever the ailment.
- TaupeRanger 5y ago
  No, not according to the statistics. You are orders of magnitude more likely to be harmed from unnecessary diagnosis/treatment (including cost and psychological damage) than to be undiagnosed and have a worse outcome as a result. We find most things that we are capable of finding.
hunter-2 5y ago
I hope this test becomes mainstream in the next few years. One of those things that the world desperately needs. There is another company in India, Tzar Labs, that has been working on a similar test and is almost ready to launch as well. https://epaper.livemint.com/Home/ShareArticle?OrgId=75ef980ce4 https://epaper.livemint.com/Home/ShareArticle?OrgId=75ef980c...
sbelskie 5y ago
> The test, which is also being piloted by NHS England in the autumn, is aimed at people at higher risk of the disease including patients aged 50 or older. Does anyone know if the study was performed with a population that matches this description? Curious if the rates are in a general population or this higher risk group.
konschubert 5y ago
If you’re tested positive, what’s the probably that you actually have cancer? (The article states 0.5% false positive rate and about 50% true positive rate, but I would need to know the the prevalence of cancer in the population to compute what I am asking for).
- konschubert 5y ago
  Let’s say 1% of ppl have cancer at any given moment - So if we test a random person, there is a 1% * 50% = 0.5% chance that person is tested positive for cancer because they have cancer. And a 0.99% * 0.5% = 0.5% chance that a person is tested false positive. This means if the test shows positive for somebody, it’s about 50-50 that they actually have cancer - correct?
  - konschubert 5y ago
    This is actually pretty good and could reasonably be used for screening in higher-risk populations.
  - tyrex2017 5y ago
    Correct. Thats why it may be a good idea to test higher risk populations or people with health issues. It could make the ratio of absolute true positives to false positives 10x better
- thebelal 5y ago
  One of the cancers they mention is pancreatic cancer. A quick Google search suggests the prevalence of pancreatic cancer in the population is 13 per 100,000. So if you gave this test with a 0.005 false positive rate and 0.5 true positive rate to 100,000 people it would miss diagnose 500 people and only correctly detect 7 cancers. So given you had a positive test result there would be a 1-(7/500)=98.6% chance you did _not_ have pancreatic cancer. Doesn't seem very useful in that light...
  - kieranmaine 5y ago
    Does this take into account age? The article says: "The test, which is also being piloted by NHS England in the autumn, is aimed at people at higher risk of the disease including patients aged 50 or older"
INGSOCIALITE 5y ago
Theranos?
- aembleton 5y ago
  This test probably needs a lot more blood than a single drop.
londons_explore 5y ago
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?
- cfontes 5y ago
  why would it matter desides for informational purposes?
  - dmichulke 5y ago
    In an extreme case you could prove that you had your "it kills you within the year" cancer already a few years ago.
    - plank_time 5y ago
      That’s what scientific studies will produce. They won’t need your particular blood for that. You as an individual only care if you have cancer at the time of the blood test.
- mritchie712 5y ago
  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.
- elif 5y ago
  I take blood tests regularly. They are very picky about sample collection time.
  - cromka 5y ago
    Same thing with stool collection.
- mrandish 5y ago
criddell 5y ago
If one wanted to invest in the people doing this kind of work, what would you buy? Grail isn't public and I'm not a venture capitalist.
- cinntaile 5y ago
  Illumina has made an offer to buy back Grail but several antitrust cases have halted the process for now.
- gww 5y ago
  There are multiple academic startup companies now trying to do cfDNA tests. They have all acquired patents from a paper or two. I would be wary about many of the early stage ones as they are not truly proven or have demonstrated scale.
dmitryminkovsky 5y ago
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 destroy my quality of life. I am not a server in a data center. I am a human with consciousness and emotions, the desire to live, and a fear of suffering and death.
- hans1729 5y ago
  One of your greatest fears in life is to be regularly checked for diseases that would end your life unless thy are detected in time? ...What? e: you mean the emotional distress caused by the process? But that's just in your head, and it's beyond irrational. Getting checked is inherently a good thing. Even if you are extremely anxious, the people who love you want you to live - this is a psychological problem that you should work through, not one with the testing
  - dmitryminkovsky 5y ago
    Yes that is right. I make no claims to being a rational being. I am at best pseudo rational. As much as I love computers, I make no claim to being one. I am a human. And yes, I do also greatly appreciate evidence based medicine. There are many terminal illnesses where there is no evidence that constant screening improves outcomes. My impression is that people successfully market products like this to give people a false sense of control tire through micromanagement where given the state of the art, control is lacking.
    - asdfasgasdgasdg 5y ago
      > My impression is that people successfully market products like this to give people a sense of control where given the state of the art, control is lacking. There can be no such evidence for a screening method like this, because it is brand new. We may find that even detection as early as Grail provides is still insufficient, but we don't and can't know yet. Certainly with many cancers earlier detection does lead to better outcomes. You also seem to be focusing on cases where screening has not improved outcomes while ignoring cases where it has.
plank_time 5y ago
Why wait until 2023 for a larger study? This is a game changing technology that should be pursued like the COVID vaccine. We should be dumping billions into this across the globe to improve its accuracy and drive costs down.
victor106 5y ago
> 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. While I think this is a great step forward, How can this be described as highly accurate when it missed identifying cancer in 48.5% of the people?
- jacquesm 5y ago
  And is only 18% accurate when looking at stage 1 cancers. https://www.theguardian.com/science/2020/mar/31/new-blood-test-can-detect-50-types-of-cancer https://www.theguardian.com/science/2020/mar/31/new-blood-te...
- doctoring 5y ago
  Cancer radiologist here! I don't know about "highly accurate", but certainly pretty fucking good. Because for most of those cancers for most populations, the asymptomatic detection rate is much, much lower. Like close to 0%. There is no general population screening test for, say, pancreatic cancer or ovarian cancer etc.
nevinera 5y ago
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 negative screening result and half get a positive one (51% successful identification), and 0.5% of the full population get a negative screening result. Those numbers are roughly equal. That doesn't make it useless by any means, but it's not nearly as 'specific' as it sounds on paper.
- gradys 5y ago
  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%
  - nevinera 5y ago
    That side-step was my actual assumption - I can't imagine that 1% of the _whole population_ currently has actionable cancer. But yes, the higher you drive the prior, the less the false-positives cost. That's a fairly normal situation - it's why they have to evaluate the cost-value of further-investigation against so many different population groups to determine the actual optimal usage. And yes, the question I was trying to prompt really is "what information would we need to have in order to know when this test is a net positive, from the patient's perspective" (and separately, "from the insurance company's perspective", since that's likely to have a very different answer).
giantg2 5y ago
If it's detecting 50 types of cancer and the patient doesn't have symptoms, do they just do a full body MRI to find the source? If so, why not just do full body scans which can find other issues, like aneurysms or the other almost 50% of positives that it missed? I get that cost is a big issue, but it seems like the test is missing a lot and you might get more bang for the buck with a periodic MRI from the perspective of the number of potential issues it can find. Either way can result in false results.
- elif 5y ago
  I mostly agree. I had a CT scan of 1/3 of my body for a specific issue, but as a consequence I got very high confidence that I was cancer-free in that portion of my body. It is such a good feeling that part of me wants to pay out-of-pocket to get the rest checked. I think though that this test has massive value in earlier detection, cost, and remote lab work.
  - giantg2 5y ago
    Dude, CTs can be risky. They use ionizing radiation, which increases your risk of cancer. It's really only an issue with repeated use, but I think there's a study out there claiming 50k early deaths each year can be attributed to repeated use of CTs. I don't have any medical background, but personally I would prefer imaging that does not use ionizing radiation when possible, just to save up some "credits" for when I may need to use the other type (like CT for possible stroke).
- doctoring 5y ago
  Hey, radiologist here. So, the question of "what next" after a positive result on one of these tests is still... open. The Grail test provides indication of likely tissue of origin, so a likely first step may be a targeted study (e.g. colonoscopy if it said a colonic source, MRI if it said pancreatic). There may be role for PET/CT as well to further stage and assess for metastases, perhaps after finding a lesion. What to do if your blood test is positive but the workup is negative? Lots of discussion but nobody is quite sure. As for a periodic full body MRI, I will say that currently uh, most of those are garbage. Unfortunately, for a full body MRI to be practical (that is, to not take hours and hours), you have to run very few sequences. (For example, a dedicated MRI of say, your brain or your liver alone could take about hour, each.) As a result, you greatly reduce your sensitivity for most pathologies, which kind of is counter to the point of the MRI to begin with.
doctoring 5y ago
Highly encourage reading the paper referred to (but not linked!) in the article: https://www.annalsofoncology.org/article/S0923-7534(21)02046-9/fulltext https://www.annalsofoncology.org/article/S0923-7534(21)02046... Some good breakdown of test performance by stage and cancer types.
Engineering-MD 5y ago
For those interested in reading the actual paper, this appears to be it (open access too): https://www.annalsofoncology.org/article/S0923-7534(21)02046-9/fulltext https://www.annalsofoncology.org/article/S0923-7534(21)02046... I’ve only skimmed it, but seen quite a few limitations, notably those with “non-malignant conditions at enrolment” (it would be nice to know more what that means), previous cancer or recent corticosteroids use were excluded. Additionally, it’s a case controlled trial which don’t always translate to screening tools (as mentioned in their own discussion). The problem with screening is that you are doing something on healthy patients, so particularly for rare cancers even a small risk of a false positive is significant. In this case it’s 99.5%. So if you test 1,000,000 people, 5000 (*correction from 500) people will come up positive. This is great for common diseases, but if it’s rare and only 1 in a million has it then you have got 5000 false positive for every 1 positive. I think this will likely be a useful test (if it translates well to a wider screening population), but it’s not as good as it first seems.
- robocat 5y ago
  > 500 people 5000 people
  - Engineering-MD 5y ago
    Yes thank you missed a zero
- myle 5y ago
  Cancer is not that rare. It ia one of the most common causes of death. I believe second to heart attacks.
- vharuck 5y ago
  >“non-malignant conditions at enrolment” (it would be nice to know more what that means) My guess is they're referring to the neoplasm behavior codes defined by the WHO in the International Classification of Diseases for Oncology (see article's references for info). Which means "malignant" is a neoplasm which has begun spreading beyond the tissue it appeared in. Non-malignant neoplasms are either benign (not likely to ever spread), borderline (could go either way), or in situ (still in the original tissue, but it will spread). North American cancer registries typically don't even bother collecting records of benign or borderline tumors. The only exceptions are brain tumors, which can be deadly without metastasizing. Registries also don't collect cervical cancer in situ records because there are so many and a lot of physicians never bothered reporting them. And finally, oncologists and epidemiologists classify urinary bladder cancer in situ as malignant because it's really hard for physicians to differentiate. Better safe than sorry, in case.
dharma1 5y ago
This is great progress. Can you get this done privately in the UK? I see only for 50+ on the NHS
DoubleDerper 5y ago
Shortcut to the source of the technology... https://grail.com/ https://grail.com/
starkd 5y ago
"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." Doesn't this seem kind of low? Just a bit better than a coin flip. Of course, it rises to 65% and 87% for certain circumstances and the false positive rate is low, but it seems like a lot of cancers could fail to be detected and give a false assurance patients are cancer free. When symptoms emerge later they may be less concerned with getting it checked out. Is this in line with standard performance of tests?
- phunehehe0 5y ago
  This is much better than a coin flip. A coin flip would give about 50% true positive rate (which is about the same as the test), but it would also give about 50% false positive rate. To put it in perspective, imagine 10 people have cancer in a population of 1000 (a rate of 10% which is too high compared to what I think the real number should be). The test would fail to identify 5 of the people with cancer, and it would say that 5 of the people without cancer have cancer. So overall it would misidentify 10 people. The coin flip would misidentify 500 people. Amusingly in this example if you have a "test" that just says nobody has cancer it would also misidentify only 10 people :) I think this is why they are reporting true positive rate and false positive rate.
  - starkd 5y ago
    I see. I guess its more important to keep false positives low than increase detection accuracy. Thank you very much for this explanation.
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rackjack 5y ago
So many tech people here thinking they know how the entire medical industry works... medical problems and the research that arises from them are staggeringly complex and messy. Please... if you've never had experience with this kind of thing, don't pretend that you do. Some uninformed person might see your comment and think you actually know something.
cronix 5y ago
One day you'll put your finger on a sensor on your phone that pricks you to get a drop of blood and analyze it right there on the spot. Kinda like square does for mobile credit card payments. Maybe that's how you'll unlock it too, which might help with phone addiction /s
bookofjoe 5y ago
What makes this even more revolutionary to me (retired anesthesiologist) is that the methodology allows for use of Theranos-style finger-prick-size blood samples rather than IV blood draw, since fragment identity is the indicator rather than level/concentration.
- wgolsen 5y ago
  The concentration of cell free DNA in blood plasma is generally in the nanograms/mL range, meaning most cfDNA assays will require at least a ~mL of plasma input for sufficient sensitivity / reproducibility. We aren’t quite at the capillary blood level of sensitivity yet.
epmaybe 5y ago
I don’t have much to add to the discussion here. Sensitivity is poor, specificity is pretty good and could be better if used as a confirmatory test(?). What I found interesting in the comments is how many people involved in healthcare lurk on a forum very much not dedicated to healthcare. Kind of cool. You all should chime in more, I learned a lot.
invisible 5y ago
There is a big discussion in this post about iatrogenics being introduced by these tests. It sounds like the fear here is that it'll tax an already burdened system with more patients (some of which just got a false positive). I'm failing to understand how that's any different from other blood tests: they signal a problem, then more has to be established to validate the signal. Nobody is saying "this test proves someone has cancer" and I'm pretty sure doctors already have to discuss how tests can be inaccurate with patients. I believe it's the case that symptoms of cancer (just like other illnesses) may be ignored exactly because there aren't any other signals to indicate cancer. Plus zebras and horses and all of that too. Perhaps someone does have symptoms but nobody connects the dots, and these tests might connect those dots. Is there some reason that this argument is invalid in medical science?
- cma 5y ago
  Chalk it up to the techno-rationalist community saying doctors can't handle bayesian statistics, on the basis of results of brain teaser surveys, and then extending that to anything related to testing or medicine.
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inadequatespace 5y ago
Took me quite some time to find the paper that seemed to describe the ML algo[1]. Pretty disappointingly domain-specific and barebones ("logistic regression"). And indeed, model form was so unimportant that it was relegated to the supplement. [2] Yet again evidence that access to data and domain knowledge trump fancy ML algos 10/10 times. [1] https://www.sciencedirect.com/science/article/pii/S0923753420360580 https://www.sciencedirect.com/science/article/pii/S092375342... [2] > Custom software was built to classify samples using source models that recognized methylation patterns per region as similar to those derived from a particular cancer type, fol- lowed by a pair of ensemble logistic regressions: one to determine cancer/non-cancer status and the other to resolve the TOO to one of the listed sites (supplementary information)

630 points by kieranmaine 5y ago

Elizabeth Holmes would be proud

This is one of those medical revolutions that I am waiting dearly for. Facilities that are not hospitals(to avoid the risk of occupying medical devices that sick people need) built to _regulary_ check up otherwise healthy people for preventive care. Heck, I have so many alerts defined on my monitoring setup for servers to watch for signals of failure before they get too big. But, my own body is not observed until something bad needs treatment. Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! All the advancement in technology in recent years, this ought to happen sooner than later.

zrail 5y ago
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.
- reacharavindh 5y ago
  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 wrong and I am not a crazy lunatic who is simply looking for attention. Although, I have never directly asked for a checkup(while being healthy) to look for disease vectors. I’ll ask and see what they say. I’d prefer if this is outside of the general healthcare system though. I don’t want to occupy Doctors, and medical labs from people who are actually sick _now_ and need those tests, and attention.
  - flemhans 5y ago
    Another Danish person here, your GP would never check you in any sort of fashion here, unless you already have (serious) symptoms.
  - horstmeyer 5y ago
    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.
    - moooo99 5y ago
      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 how much money goes to waste for useless treatments with something like homeopathy while people who really need proper treatment are stuck with the cheapest option that is paid for. [1] https://www.bundesgesundheitsministerium.de/checkup.html https://www.bundesgesundheitsministerium.de/checkup.html (German)
      - horstmeyer 5y ago
        Thanks for the correction, that was what my doctor told me. But maybe I also misunderstood him.
  - refurb 5y ago
    This approach actually works really well for conserving healthcare dollars. If a doctor feels like nothing is wrong, 99% of the time they’ll be right. Sucks to be that 1% where you die of a cancer that would have been caught, but that’s the trade off. The marginal return of each dollars spent on screening goes down quickly. At a population level you can’t justify it, but at a personal level you can.
- vmception 5y ago
  That’s not good enough for cancer because we dont even know how fast or slow it grows. Even if it cancer cells multiplied at the rate of a fetus that would be too fast for an annual physical. Congratulations, death. Ideally something like a wearable computer or nanomachines in your blood stream automatically report anomalies for individualized treatment.
  - danuker 5y ago
    > Even if cancer cells multiplied at the rate of a fetus I suspect at least some cancers multiply slower than that, because they work against the rest of the cells.
  - dryrun 5y ago
    Given the amount of "I don't want bill gates injecting me a tracker!", I have some idea of how a conversation with the same people about nano machines in their body would go. I would also bet on the time-frame between this and the availability of your data on the servers of your health insurance.
    - vmception 5y ago
      Not my problem, human cancers stay in there own bodies and are not communicable To our knowledge
      - jacquesm 5y ago
        Not normally, no. But there are some puzzling exceptions: https://www.discovermagazine.com/health/the-cancers-that-are-contagious https://www.discovermagazine.com/health/the-cancers-that-are...
        vmception 5y ago
        These are all in animals and I specified human cancers for that specific reason, thanks for the article though, I only knew about the Tasmanian Devil one
- Clampower 5y ago
  This is not true in the Netherlands. You don’t get any tests if there is nothing wrong. Healthcare in this country scares me.
  - pelorat 5y ago
    You can ask for a blood test though and ask that they check specific markers. But I agree that huisartsen are too dismissive in general.
    - egeozcan 5y ago
      Same in Germany (Hausärzte). Even if you have a specific complaint, you'll just be told to go home and drink a lot of water. They just don't have the capacity to test for causes. I'm not sure if I can even pay someone to make extensive tests here. Never tried. Perhaps one needs to go to the US for that.
  - the-dude 5y ago
    Take control. Regular doctors in NL are basically there to prevent you from getting care. Say you want a blood test, and what for. I they don't cooperate, move to the next doctor.
  - danuker 5y ago
    In the US, the medical system was (and might still be) the top third cause of death, of which 5/6ths were due to medicine side-effects. https://nutritionfacts.org/video/how-doctors-responded-to-being-named-a-leading-killer/ https://nutritionfacts.org/video/how-doctors-responded-to-be... I suspect doctors in the Netherlands are taught not to over-diagnose. Are they paid through national insurance?
    - goodpoint 5y ago
      Yes, the US medical system is a disaster.
  - refurb 5y ago
    Really? Not even a blood pressure check or a physician listening to your lungs or just examine your skin for weird moles? That’s terrible.
- postingawayonhn 5y ago
  I've never lived anywhere where this was common. The public health system can't afford to fund it and most of the population doesn't want to (or can't afford to) pay for it themselves.
xwdv 5y ago
My experience is people don’t really care much about their bodies beyond the aesthetics. Most treat it like a dumpster and ingest whatever crap feels good and hope for the best. Caring too much makes you some sort of health freak in their eyes, with way too much time on your hands.
- carlmr 5y ago
  I'm not sure this is true. At least in my friend circle most people put a lot of care into their nutrition and fitness. Maybe talk to your friends about it and get them to be healthier?
  - handrous 5y ago
    How do you think we get the rates of diabetes and obesity we have in the US, without that being true for most people in most places and in most social circles? Rich social networks tend to live much healthier lifestyles than average. Normal is fried starch and tens to hundreds of ounces of soda more days than not, and exercise is that maybe you golf sometimes or play in a seasonal company softball league (drinking way more calories than you're burning, almost certainly).
- danuker 5y ago
  The top risk factors for death confirm what you say, sadly. https://ourworldindata.org/causes-of-death#the-number-of-deaths-by-risk-factor https://ourworldindata.org/causes-of-death#the-number-of-dea...
sbelskie 5y ago
A big part of this is the fact that learning information (about a disease or condition) early is often NOT the same thing as learning information that will change a patient’s clinical outcome.
- radu_floricica 5y ago
  I never understood this. I mean I totally get the concept, but I don't get how it came to influence policy. Put it like this: how many people are you willing to kill to make sure people don't find out they're sick? Because that's what it boils down to. And it sounds... sociopathic.
  - sbelskie 5y ago
    I’m not sure I understand what you mean. It seems like you’re framing my motivation as not wanting people to know that they are sick and being willing to trade peoples lives to achieve that outcome, which I don’t think is at all what my above comment says.
    - radu_floricica 5y ago
      It is how I understood it, sorry about that. What did you mean?
  - dabbledash 5y ago
    The idea is that treatment also has risks and false positives are an issue. If you gave a mammogram to every 20 year old woman, you would end up doing a large number of unnecessary biopsies and you’d find almost no real cancer. In the end, you’d lose more people than you would save. Or that’s the idea. I’m no expert in this but it makes sense to me conceptually.
    - JumpCrisscross 5y ago
      > If you gave a mammogram to every 20 year old woman, you would end up doing a large number of unnecessary biopsies and you’d find almost no real cancer If you gave a mammogram to every 20-year old, you wouldn't do a biopsy when you got a positive. You'd increase monitoring and maybe suggest lifestyle changes. The same way we don't immediately catherize everyone who comes back with high cholesterol.
Gatsky 5y ago
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.
- junon 5y ago
  "Preventative care" refers to the field of medicine called preventative medicine/care/health, which specifically aims at making regular checkups and other monitoring facilities free and accessible in order to improve health via early-detection. Oftentimes, doing these sorts of things lowers your insurance premiums or makes costs lower if something does happen (not always, but sometimes). These sorts of things are also generally free as it costs the insurance company less in the long run if you're doing them frequently enough. Perhaps a bit of a misnomer, but "preventative care" doesn't necessarily mean medicinal prevention of any sort.
- dannyw 5y ago
  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.
  - carlmr 5y ago
    Ransomware infecting one machine or all machines including backups would also be a good analogy.
  - jacquesm 5y ago
    > 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.
  - Gatsky 5y ago
    I’m not saying it isn’t a great development. It certainly adds an option for early detection of some cancers where there previously were none. But it isn’t cancer prevention. It is a highly sophisticated technical undertaking which for educated and motivated patients in well resourced health systems will reduce cancer mortality and morbidity by some increment. Depending on many factors this could be a big or small increment. In the real world the efficacy will be less than what the trial shows. It is also likely that Grail (with north of $1 billion in VC funding) will charge as much as they can for this test. The size of the trials necessary to prove efficacy means that there will be highly constrained competition in this space. The distinction with prevention is important, because we ultimately must aim for preventing almost all cancers, and not be content with anything less than that. Disclaimer: I’m an Oncologist.
Tolyzz 5y ago
Cause things break down all the time. And everything can look like early signs of trouble. There are lot useless docs and surgeons waiting to perform unnecessary expensive procedures much like building contractors. Oh that pipe is leaking let's just replace this entire load bearing wall etc cause we have this new cool machine that can. Second opinions are over rated cause the majority don't care. There is an endless demand for their trade. My dad lost his hearing at 35 after they performed surgery to remove a tumor they detected. They detected the same Tumor in my brother when he was in his 20s and wanted to operate with no guarantee of hearing preservation. He declined. He is going to turn 40 soon and would have most likely been deaf for 20 years if he had gone through with it. Minor issues with his balance but other than that he is fine even though tumor gets tracked every couple years and is still growing.
- BallyBrain 5y ago
  This sounds like a regulation and education problem to me. early detection doesn't have to mean treatment, it could just be monitoring and change of lifestyle.
jacquesm 5y ago
Regularly checking people that are otherwise healthy for cancer will turn up a lot of cancer through false positives or slowly growing ones, will lead to a lot of unnecessary intervention and will in fact lead to a reduction in quality of life and lifespan. This is one of the reasons why exhaustive cancer screening (which was more costly in the past but could have been done) was not promoted, it had nothing to do with ability, but everything to do with outcomes. Those cancers where checkups are useful we already do regular screenings for. For aggressive cancers - the ones that are really problematic - you would have to do such a test too frequently to make any real difference, for instance, if you were to test annually you'd be on average 6 months away from your next test, plenty of time for such a cancer to develop and kill you. So this is not the kind of breakthrough that you may think it is.
- bruce343434 5y ago
  Who are "we"? I'm certainly not "regularly" screened.
  - jacquesm 5y ago
    That's your choice, assuming you live in a developed country. Assuming the United States see here: https://www.cdc.gov/cancer/dcpc/prevention/screening.htm https://www.cdc.gov/cancer/dcpc/prevention/screening.htm and if elsewhere consult your local CDC equivalent.
    - postingawayonhn 5y ago
      Current screening methods tend to be costly and/or uncomfortable for the person being screened. A simple blood test could lead to higher uptake and more regular screening.
- tarsinge 5y ago
  > Those cancers where checkups are useful we already do regular screenings for. More like “are <practical given available tests> and useful”. Regarding your last paragraph cancer screening seems very rare except for one or two types (at least where I live), so statistically yes an annual test will miss the worst case you presented, but for the vast majority it will be a huge improvement.
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TaupeRanger 5y ago
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 symptoms or other noticeable problems. Further, for many things that can be detected we can't really do much about, so by detecting it early you are just reducing the amount of life they have left without worrying about their disease, or causing unnecessary treatment (which includes unnecessary damage, cost, stress, etc.)
- throwawaynotmd 5y ago
  The argument you’re making has always bothered me because it’s hiding the ball. If finding something that otherwise carries no symptoms is best left untreated, then the fact that you found it should make no difference to the decision. The doctor should say that the best course of action is to do nothing. More information can never be harmful. If you know information is best not acted on in the abstract, then you also know you should not act on it in particular. So what you really mean but have left unspoken is one of two things. First, that doctors are untrustworthy people who make recommendations and decisions based on concerns other than their patient’s wellbeing, such as covering their asses from lawsuits or making more money. But rather than fix that, you would rather keep patients more ignorant and away from the doctor in the first place. Which actively harms people who do have honest doctors. That is, your approach of not testing hurts people with honest doctors to protect people with dishonest doctors. Or second, if you take dumb patients as the problem, you are willing to hurt people with good decision making ability (who would heed their good doctor’s advice to leave the possible ailment untreated) so you can protect people with bad decision making. Because many times, these tests will uncover things that obviously need treatment. They will save many lives. But because more stupid people will hurt themselves, then no one should have access to them. The political and moral assumptions built into these positions are immense and yet the medical field tucks those away and pretends that this is just a purely scientific truth, that someone running more harmless tests is actually inherently harmful. That is a lie! And a very nasty one at that.
hannob 5y ago
The reason this is not happening isn't a technical one. It's that people with a medical background will tell you this isn't a healthy utopia, it's a nightmare. Medical tests are complicated. They often have significant false positive and false negative rates. Testing people at scale increases the number of people with wrong test results and can cause harm if you start treating people based on wrong test results. The more healthy people you test the more false positives you get. The goal of evidence based medicine is to use tests when they can help. It's not to test as many people as possible. This is reasonable. You want to improve patient's lives. Whether or not a test is improving patient's lives is often not easy to answer and has to consider many things.
- axxto 5y ago
  The point of this is not that you get a definitive diagnosis; it's just a somewhat reliable marker on whether you may need to be concerned and get more accurate (but more harmful) imaging or invasive tests to rule out something.
  - dangerlibrary 5y ago
    You only need one false positive test result that ends up with a colonoscopy to understand how costly and uncomfortable these errors can be. (I'm using an uncomfortable and illustrative example, but a colonoscopy is honestly pretty safe and boring as invasive clinical diagnostic procedures go)
    - theptip 5y ago
      Perhaps a better example than you intended -- recently colonoscopies are being considered more risky as a regular screening tool, because the procedure itself can result in harms, including (rarely) death. Not an expert here, but it seems they are still used in a fairly wide age group, but the recent trend is to be more cautious about their usage, as particularly for older patients they are more risky vs. the potential benefits. [1] However I think this concern would be reduced if we had better first-line screening like the tests in TFA; the harms come from using a relatively-risky assay like colonoscopy for regular screening in healthy individuals, whereas if we had better noninvasive screening, the colonoscopy could be reserved for patients where there's a higher probability of a positive diagnosis. [1]: https://jamanetwork.com/journals/jama/fullarticle/2529486 https://jamanetwork.com/journals/jama/fullarticle/2529486
dukeofdoom 5y ago
One issue is that your body may have all types of tissues that might be precancerous or slow growing cancerous growths that the test will identify. To get to them and remove them would do far more damage than leaving them alone. Even with things like prostate cancer, which is fairly easy to get to. Leaving it alone, is often the right choice depending on the age of the patient and speed of growth of the cancer.
andai 5y ago
I expect this won't catch on until it becomes a wearable technology, and then it will catch on overnight.
DoreenMichele 5y ago
Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! We can and plenty of people do, usually with tools like health journals and smart watches recording biometrics.
matheusmoreira 5y ago
> Why can’t we observe ourselves medically and analyze that record for early signs of trouble before it becomes serious?! Maybe one day we'll have cybernetic implants that can constantly monitor our health. Hopefully it won't turn into a privacy nightmare.

xiphias2 5y ago

Galleri test looks great, but it is available only in US and UK. I wish they would allow private patients in other countries to take the test somehow.

Zenst 5y ago

Whole area of having tests that give definitive answers in the field of health is the one area in which it can't get enough of. Biggest issue health wise many have is time from issue to getting a correct diagnoses, whatever the ailment.

TaupeRanger 5y ago
No, not according to the statistics. You are orders of magnitude more likely to be harmed from unnecessary diagnosis/treatment (including cost and psychological damage) than to be undiagnosed and have a worse outcome as a result. We find most things that we are capable of finding.

hunter-2 5y ago

I hope this test becomes mainstream in the next few years. One of those things that the world desperately needs. There is another company in India, Tzar Labs, that has been working on a similar test and is almost ready to launch as well. https://epaper.livemint.com/Home/ShareArticle?OrgId=75ef980ce4 https://epaper.livemint.com/Home/ShareArticle?OrgId=75ef980c...

sbelskie 5y ago

> The test, which is also being piloted by NHS England in the autumn, is aimed at people at higher risk of the disease including patients aged 50 or older. Does anyone know if the study was performed with a population that matches this description? Curious if the rates are in a general population or this higher risk group.

konschubert 5y ago

If you’re tested positive, what’s the probably that you actually have cancer? (The article states 0.5% false positive rate and about 50% true positive rate, but I would need to know the the prevalence of cancer in the population to compute what I am asking for).

konschubert 5y ago
Let’s say 1% of ppl have cancer at any given moment - So if we test a random person, there is a 1% * 50% = 0.5% chance that person is tested positive for cancer because they have cancer. And a 0.99% * 0.5% = 0.5% chance that a person is tested false positive. This means if the test shows positive for somebody, it’s about 50-50 that they actually have cancer - correct?
- konschubert 5y ago
  This is actually pretty good and could reasonably be used for screening in higher-risk populations.
- tyrex2017 5y ago
  Correct. Thats why it may be a good idea to test higher risk populations or people with health issues. It could make the ratio of absolute true positives to false positives 10x better
thebelal 5y ago
One of the cancers they mention is pancreatic cancer. A quick Google search suggests the prevalence of pancreatic cancer in the population is 13 per 100,000. So if you gave this test with a 0.005 false positive rate and 0.5 true positive rate to 100,000 people it would miss diagnose 500 people and only correctly detect 7 cancers. So given you had a positive test result there would be a 1-(7/500)=98.6% chance you did _not_ have pancreatic cancer. Doesn't seem very useful in that light...
- kieranmaine 5y ago
  Does this take into account age? The article says: "The test, which is also being piloted by NHS England in the autumn, is aimed at people at higher risk of the disease including patients aged 50 or older"

INGSOCIALITE 5y ago

Theranos?

aembleton 5y ago
This test probably needs a lot more blood than a single drop.

londons_explore 5y ago

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?

cfontes 5y ago
why would it matter desides for informational purposes?
- dmichulke 5y ago
  In an extreme case you could prove that you had your "it kills you within the year" cancer already a few years ago.
  - plank_time 5y ago
    That’s what scientific studies will produce. They won’t need your particular blood for that. You as an individual only care if you have cancer at the time of the blood test.
mritchie712 5y ago
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.
elif 5y ago
I take blood tests regularly. They are very picky about sample collection time.
- cromka 5y ago
  Same thing with stool collection.
mrandish 5y ago

criddell 5y ago

If one wanted to invest in the people doing this kind of work, what would you buy? Grail isn't public and I'm not a venture capitalist.

cinntaile 5y ago
Illumina has made an offer to buy back Grail but several antitrust cases have halted the process for now.
gww 5y ago
There are multiple academic startup companies now trying to do cfDNA tests. They have all acquired patents from a paper or two. I would be wary about many of the early stage ones as they are not truly proven or have demonstrated scale.

dmitryminkovsky 5y ago

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 destroy my quality of life. I am not a server in a data center. I am a human with consciousness and emotions, the desire to live, and a fear of suffering and death.

hans1729 5y ago
One of your greatest fears in life is to be regularly checked for diseases that would end your life unless thy are detected in time? ...What? e: you mean the emotional distress caused by the process? But that's just in your head, and it's beyond irrational. Getting checked is inherently a good thing. Even if you are extremely anxious, the people who love you want you to live - this is a psychological problem that you should work through, not one with the testing
- dmitryminkovsky 5y ago
  Yes that is right. I make no claims to being a rational being. I am at best pseudo rational. As much as I love computers, I make no claim to being one. I am a human. And yes, I do also greatly appreciate evidence based medicine. There are many terminal illnesses where there is no evidence that constant screening improves outcomes. My impression is that people successfully market products like this to give people a false sense of control tire through micromanagement where given the state of the art, control is lacking.
  - asdfasgasdgasdg 5y ago
    > My impression is that people successfully market products like this to give people a sense of control where given the state of the art, control is lacking. There can be no such evidence for a screening method like this, because it is brand new. We may find that even detection as early as Grail provides is still insufficient, but we don't and can't know yet. Certainly with many cancers earlier detection does lead to better outcomes. You also seem to be focusing on cases where screening has not improved outcomes while ignoring cases where it has.

plank_time 5y ago

Why wait until 2023 for a larger study? This is a game changing technology that should be pursued like the COVID vaccine. We should be dumping billions into this across the globe to improve its accuracy and drive costs down.

victor106 5y ago

> 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. While I think this is a great step forward, How can this be described as highly accurate when it missed identifying cancer in 48.5% of the people?

jacquesm 5y ago
And is only 18% accurate when looking at stage 1 cancers. https://www.theguardian.com/science/2020/mar/31/new-blood-test-can-detect-50-types-of-cancer https://www.theguardian.com/science/2020/mar/31/new-blood-te...
doctoring 5y ago
Cancer radiologist here! I don't know about "highly accurate", but certainly pretty fucking good. Because for most of those cancers for most populations, the asymptomatic detection rate is much, much lower. Like close to 0%. There is no general population screening test for, say, pancreatic cancer or ovarian cancer etc.

nevinera 5y ago

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 negative screening result and half get a positive one (51% successful identification), and 0.5% of the full population get a negative screening result. Those numbers are roughly equal. That doesn't make it useless by any means, but it's not nearly as 'specific' as it sounds on paper.

gradys 5y ago
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%
- nevinera 5y ago
  That side-step was my actual assumption - I can't imagine that 1% of the _whole population_ currently has actionable cancer. But yes, the higher you drive the prior, the less the false-positives cost. That's a fairly normal situation - it's why they have to evaluate the cost-value of further-investigation against so many different population groups to determine the actual optimal usage. And yes, the question I was trying to prompt really is "what information would we need to have in order to know when this test is a net positive, from the patient's perspective" (and separately, "from the insurance company's perspective", since that's likely to have a very different answer).

giantg2 5y ago

If it's detecting 50 types of cancer and the patient doesn't have symptoms, do they just do a full body MRI to find the source? If so, why not just do full body scans which can find other issues, like aneurysms or the other almost 50% of positives that it missed? I get that cost is a big issue, but it seems like the test is missing a lot and you might get more bang for the buck with a periodic MRI from the perspective of the number of potential issues it can find. Either way can result in false results.

elif 5y ago
I mostly agree. I had a CT scan of 1/3 of my body for a specific issue, but as a consequence I got very high confidence that I was cancer-free in that portion of my body. It is such a good feeling that part of me wants to pay out-of-pocket to get the rest checked. I think though that this test has massive value in earlier detection, cost, and remote lab work.
- giantg2 5y ago
  Dude, CTs can be risky. They use ionizing radiation, which increases your risk of cancer. It's really only an issue with repeated use, but I think there's a study out there claiming 50k early deaths each year can be attributed to repeated use of CTs. I don't have any medical background, but personally I would prefer imaging that does not use ionizing radiation when possible, just to save up some "credits" for when I may need to use the other type (like CT for possible stroke).
doctoring 5y ago
Hey, radiologist here. So, the question of "what next" after a positive result on one of these tests is still... open. The Grail test provides indication of likely tissue of origin, so a likely first step may be a targeted study (e.g. colonoscopy if it said a colonic source, MRI if it said pancreatic). There may be role for PET/CT as well to further stage and assess for metastases, perhaps after finding a lesion. What to do if your blood test is positive but the workup is negative? Lots of discussion but nobody is quite sure. As for a periodic full body MRI, I will say that currently uh, most of those are garbage. Unfortunately, for a full body MRI to be practical (that is, to not take hours and hours), you have to run very few sequences. (For example, a dedicated MRI of say, your brain or your liver alone could take about hour, each.) As a result, you greatly reduce your sensitivity for most pathologies, which kind of is counter to the point of the MRI to begin with.

doctoring 5y ago

Highly encourage reading the paper referred to (but not linked!) in the article: https://www.annalsofoncology.org/article/S0923-7534(21)02046-9/fulltext https://www.annalsofoncology.org/article/S0923-7534(21)02046... Some good breakdown of test performance by stage and cancer types.

Engineering-MD 5y ago

For those interested in reading the actual paper, this appears to be it (open access too): https://www.annalsofoncology.org/article/S0923-7534(21)02046-9/fulltext https://www.annalsofoncology.org/article/S0923-7534(21)02046... I’ve only skimmed it, but seen quite a few limitations, notably those with “non-malignant conditions at enrolment” (it would be nice to know more what that means), previous cancer or recent corticosteroids use were excluded. Additionally, it’s a case controlled trial which don’t always translate to screening tools (as mentioned in their own discussion). The problem with screening is that you are doing something on healthy patients, so particularly for rare cancers even a small risk of a false positive is significant. In this case it’s 99.5%. So if you test 1,000,000 people, 5000 (*correction from 500) people will come up positive. This is great for common diseases, but if it’s rare and only 1 in a million has it then you have got 5000 false positive for every 1 positive. I think this will likely be a useful test (if it translates well to a wider screening population), but it’s not as good as it first seems.

robocat 5y ago
> 500 people 5000 people
- Engineering-MD 5y ago
  Yes thank you missed a zero
myle 5y ago
Cancer is not that rare. It ia one of the most common causes of death. I believe second to heart attacks.
vharuck 5y ago
>“non-malignant conditions at enrolment” (it would be nice to know more what that means) My guess is they're referring to the neoplasm behavior codes defined by the WHO in the International Classification of Diseases for Oncology (see article's references for info). Which means "malignant" is a neoplasm which has begun spreading beyond the tissue it appeared in. Non-malignant neoplasms are either benign (not likely to ever spread), borderline (could go either way), or in situ (still in the original tissue, but it will spread). North American cancer registries typically don't even bother collecting records of benign or borderline tumors. The only exceptions are brain tumors, which can be deadly without metastasizing. Registries also don't collect cervical cancer in situ records because there are so many and a lot of physicians never bothered reporting them. And finally, oncologists and epidemiologists classify urinary bladder cancer in situ as malignant because it's really hard for physicians to differentiate. Better safe than sorry, in case.

dharma1 5y ago

This is great progress. Can you get this done privately in the UK? I see only for 50+ on the NHS

DoubleDerper 5y ago

Shortcut to the source of the technology... https://grail.com/ https://grail.com/

starkd 5y ago

"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." Doesn't this seem kind of low? Just a bit better than a coin flip. Of course, it rises to 65% and 87% for certain circumstances and the false positive rate is low, but it seems like a lot of cancers could fail to be detected and give a false assurance patients are cancer free. When symptoms emerge later they may be less concerned with getting it checked out. Is this in line with standard performance of tests?

phunehehe0 5y ago
This is much better than a coin flip. A coin flip would give about 50% true positive rate (which is about the same as the test), but it would also give about 50% false positive rate. To put it in perspective, imagine 10 people have cancer in a population of 1000 (a rate of 10% which is too high compared to what I think the real number should be). The test would fail to identify 5 of the people with cancer, and it would say that 5 of the people without cancer have cancer. So overall it would misidentify 10 people. The coin flip would misidentify 500 people. Amusingly in this example if you have a "test" that just says nobody has cancer it would also misidentify only 10 people :) I think this is why they are reporting true positive rate and false positive rate.
- starkd 5y ago
  I see. I guess its more important to keep false positives low than increase detection accuracy. Thank you very much for this explanation.

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rackjack 5y ago

So many tech people here thinking they know how the entire medical industry works... medical problems and the research that arises from them are staggeringly complex and messy. Please... if you've never had experience with this kind of thing, don't pretend that you do. Some uninformed person might see your comment and think you actually know something.

cronix 5y ago

One day you'll put your finger on a sensor on your phone that pricks you to get a drop of blood and analyze it right there on the spot. Kinda like square does for mobile credit card payments. Maybe that's how you'll unlock it too, which might help with phone addiction /s

bookofjoe 5y ago

What makes this even more revolutionary to me (retired anesthesiologist) is that the methodology allows for use of Theranos-style finger-prick-size blood samples rather than IV blood draw, since fragment identity is the indicator rather than level/concentration.

wgolsen 5y ago
The concentration of cell free DNA in blood plasma is generally in the nanograms/mL range, meaning most cfDNA assays will require at least a ~mL of plasma input for sufficient sensitivity / reproducibility. We aren’t quite at the capillary blood level of sensitivity yet.

epmaybe 5y ago

I don’t have much to add to the discussion here. Sensitivity is poor, specificity is pretty good and could be better if used as a confirmatory test(?). What I found interesting in the comments is how many people involved in healthcare lurk on a forum very much not dedicated to healthcare. Kind of cool. You all should chime in more, I learned a lot.

invisible 5y ago

There is a big discussion in this post about iatrogenics being introduced by these tests. It sounds like the fear here is that it'll tax an already burdened system with more patients (some of which just got a false positive). I'm failing to understand how that's any different from other blood tests: they signal a problem, then more has to be established to validate the signal. Nobody is saying "this test proves someone has cancer" and I'm pretty sure doctors already have to discuss how tests can be inaccurate with patients. I believe it's the case that symptoms of cancer (just like other illnesses) may be ignored exactly because there aren't any other signals to indicate cancer. Plus zebras and horses and all of that too. Perhaps someone does have symptoms but nobody connects the dots, and these tests might connect those dots. Is there some reason that this argument is invalid in medical science?

cma 5y ago
Chalk it up to the techno-rationalist community saying doctors can't handle bayesian statistics, on the basis of results of brain teaser surveys, and then extending that to anything related to testing or medicine.

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inadequatespace 5y ago

Took me quite some time to find the paper that seemed to describe the ML algo[1]. Pretty disappointingly domain-specific and barebones ("logistic regression"). And indeed, model form was so unimportant that it was relegated to the supplement. [2] Yet again evidence that access to data and domain knowledge trump fancy ML algos 10/10 times. [1] https://www.sciencedirect.com/science/article/pii/S0923753420360580 https://www.sciencedirect.com/science/article/pii/S092375342... [2] > Custom software was built to classify samples using source models that recognized methylation patterns per region as similar to those derived from a particular cancer type, fol- lowed by a pair of ensemble logistic regressions: one to determine cancer/non-cancer status and the other to resolve the TOO to one of the listed sites (supplementary information)