Experimental blood test detects cancer up to four years before symptoms appear

https://www.scientificamerican.com/article/experimental-blood-test-detects-cancer-up-to-four-years-before-symptoms-appear/

by prawn • 6 years ago

650 189 6 years ago

scientificamerican.com

scandox2• 6 years ago

This makes me think of an article I read about prostate cancer detection. Apparently, it is possible to detect the possibility of prostate cancer many, many years before it is going to develop with a more sensitive, modern test. Once the detection is made both patient and doctor are not in a position to ignore it. At the same time treatment may well be premature or not recommended. But the doctor is left with a dilemma because it may appear they did not take action on something they knew.

That at least was the general topic of the article. The question it raises is interesting: is it sometimes too early to know.

hannob• 6 years ago

This is widely discussed in medical circles, but the real problem is a different one: It's sometimes hard to know what helps and what doesn't.

You may see something that may lead to a cancer. But you really don't know. It may be a) harmless, b) lead to a cancer, c) a mistake in your test. If it's b) then treating it early is good. If it's a) or c) then treating it early will ultimately harm the patient. If your test finds mainly a) and c) then your test may ultimately do more harm than good.

sterlind• 6 years ago

Isn't this the idea behind watchful waiting? You have an early signal so you follow up with periodic tests to see if it goes away or shows signs of malignancy.

Eventually we'll have studies that show the conditional probability of different cancer outcomes based on these early signals, and from there we'll have a protocol to get the best outcomes, reducing the chance of malignant cancer while minimizing cost and medical intervention.

forgotmypwbctbi• 6 years ago

it is at minimum an early warning for lifestyle change

jfk13• 6 years ago

Even if you could predict with certainty that the patient is going to develop cancer in 10 years, and you know of a course of treatment you could undertake that will ultimately prevent that cancer developing, you still may not be able to say whether this is the best use of the patient's time and resources today. (And the patient can't be sure either.)

DanBC2• 6 years ago

Early detection of prostate cancer with PSA testing and digital rectal exam: https://www.hardingcenter.de/en/early-detection-prostate-can...

With or without screening, 7 out of every 1,000 men died from prostate cancer over a time period 11 years.

But in the screening group additional men were harmed by side effects of surgery.

shard6• 6 years ago

I am not sure what percentage of patients still require surgery as opposed to the more modern radiation treatments. My father's radiation treatment was painless except for the placement of the 3 tracking markers in his prostate, and although his side effects were more severe than most, they have disappeared after 3 months. So if prostate cancer treatment does not affect eventual death from the cancer over 11 years, then the questions are whether the treatment improve QOL during the 11 years, and whether the onset is delayed within that 11 years.

pintxo12• 6 years ago

Prostate cancer is somewhat unique by having a very sensitive blood marker (PSA) being available which can be monitored easily over time.

And yes, there is an (I would say) ongoing debate about the value of using PSA to detect early cancers. Obviously detecting cancer early is a win. But the downside of this early detection is over-treatment of low-risk cancers.

Standard therapy for prostate cancer is the removal of the prostate, but this surgery has a somewhat high (up to ~10-15%) risk of impotence and incontinence (depending on the quality of the surgeon), which can obviously impact life quality quite massively.

Current strategy (in the US) seems to basically stop broad usage of PSA testing, which gets rid of the problem of detecting low risk cancers, but at the cost of delaying the identification of high risk cancers. This is visible in the falling rate of newly diagnosed prostate cancer patients in the US.

This feels like not solving the actual problem (distinguishing low risk from high risk tumors) but glossing over the problem by not actively working on detecting it anymore.

DanBC2• 6 years ago

but at the cost of delaying the identification of high risk cancers. This is visible in the falling rate of newly diagnosed prostate cancer patients in the US.

Importantly, it doesn't seem to affect mortality rate of prostate cancer, nor all cause mortality.

People focus a lot on 5 year survival rate, but sometimes they don't really understand what this means. If I die at 75 does it matter if my cancer is detected when I'm 68 vs 73?

kiba• 6 years ago

Makes me wonder if there are similarly low risk medication that fight cancer.

HeadsUpHigh5• 6 years ago

Prostate cancer is somewhat unique by having a very sensitive blood marker (PSA) being available which can be monitored easily over time.

Cancer antigens such as PSA and CA-125 can also increase due to non-cancerous causes. Pretty much all of them increase in any kind of inflammation whether it is due to bacteria or something else and more. So their main use is getting a baseline once the cancer is diagnosed and monitoring it later on.

Funny story, a professor once had a patient with prostate cancer, treated and cancer free afterwards. Every 6 months the patient would visit for screening and his PSA was through the roof( think >1k while normal levels are at most around 3ng/mL). After performing CT scans etc the patient was found cancer free. Another PSA test would return normal after a couple days. This story repeated several times with the professor slowly sliding into madness from it.

Turns out the patient was getting anxious about the screening the day before so he smoked some weed which increases PSA secretion. And of course weed is illegal here so he didn't want to admit it.

abalone16• 6 years ago

It is also visible in the increase in metastatic prostate cancer.

I’ve spoken with the chief surgeons of two major prostate cancer centers. They agree this was not a good recommendation by the US task force.

Also I should add that the risk of impotence / dysfunction is much higher with late-detected cancers.

https://jamanetwork.com/journals/jamaoncology/fullarticle/25...

sradman3• 6 years ago

Stomach cancer, for one, is easy to remove surgically if detected early but it does not exhibit symptoms until it is often too late. I suspect that early warnings would trigger targeted endoscopy procedures. The pathogenesis of prostate cancer may not be representative of other cancers.

elric• 6 years ago

Same with bowel cancer. Easily treated if found early. There are at home test kits which can detect small amounts of blood in stool -- often an early warning sign. And while unpleasant sounding, colo(no)scopy is pretty uninvasive.

henearkr3• 6 years ago

This is an incredible confusion, and I'm angry to see so many medical authorities and administrations taking the same stance: no, it's never too early to know. The more the information the better everything. What could be too early is to act, supposing that by "act" is meant any predefined medical action. However why would it be any "too soon" for an awareness awakening by the sick individual that would bring a healthier lifestyle?

Last thing I'd like to add, you just have to tell the individual about the trade-off and risks of the early act too, and this additional information will be enough to cancel any supposed danger of the early diagnostics information.

When you think that giving some information is dangerous, then actually it's because you need to provide the targeted individual even more of what info you have.

foldr9• 6 years ago

it's never too early to know

I don't see this. Suppose, hypothetically, that we could detect right now every illness or condition that you're ever likely to develop in the course of your life. Do you really want to read through that list? You're better off not worrying about it and enjoying your life.

pintxo12• 6 years ago

I pretty much agree with your points. But this is not what we see in reality today.

I believe that part of today's problem is knowledge, interest and incentives.

- About 40% of patients (in general) do not care enough about their health and delegate all decision making to the doctor.

- I am simplifying here: If you ask a surgeon about the best therapy for your cancer, the answer will most likely be surgery. If the same patient would ask a radiologist, the answer will most likely be radiation. Which we might attribute to people more likely to believe in their own line of work. But in reality this might be more influenced by doctors being financially driven by their administrators to maximize patient throughput.

l33tman3• 6 years ago

It's just hard to take in that info.. Your average patient is not really capable, especially when delivered life-changing information and requiring THEM to decide what life-changing action to take. Most in that situation defers to what the physician recommends, which brings us back to the current situation.

One root problem here is the lack of a firm connection between test result and long-term prognosis. You can have a supersensitive test, but if the prognosis varies wildly anyway and the possible procedure to do carries significant risk, the test has limited value.

One general rule is that you should not order a test unless you're prepared to act on it, and the guidelines for when to act on the PSA levels are still debated.

There are lots of other tests and pathologies and remedies that make sense to screen for (that can, like you say, make the patient go for a more healthy lifestyle etc).

thaumasiotes5• 6 years ago

Apparently, it is possible to detect the possibility of prostate cancer many, many years before it is going to develop with a more sensitive, modern test. Once the detection is made both patient and doctor are not in a position to ignore it.

I'll tell you a story from when my mother was in medical school.

There was a class one day in which the students were given a pile of slides of prostate samples and told to identify the cancerous one. Many, many questions ensued, of the form "This looks kind of cancerous. Is this the slide?"

Eventually the professor announced to the class "look, there's a bit of cancer in everyone's prostate. The goal here is to find the slide with OBVIOUS cancer."

And this is, to the best of my knowledge, still the state of things in prostate cancer today. All prostates are cancerous. A man who lived long enough would eventually be killed by prostate cancer -- a cancer detectable long, long before he actually died. But most men die of other things, because prostate cancer develops so slowly.

Ignoring prostate cancer is in fact a common way to handle it, if the patient is old enough or the cancer is small enough when detected. The technical term for this is "watchful waiting".

pintxo12• 6 years ago

A pathologist once told me the likelihood of having prostate cancer is basically you age: 50 -> 50%, 70 -> 70%, ...

endymi0n• 6 years ago

I've heard it phrased by a doctor as "Almost every man dies WITH prostate cancer. Almost no man dies FROM prostate cancer."

Someone2• 6 years ago

As a corollary, there’s much discussion about the benefits of screening for prostate cancer. The procedure itself carries some risks, and it can lead to operations that add further risks, a significant fraction of which statistically aren’t necessary.

https://en.wikipedia.org/wiki/Prostate_cancer_screening:

“A 2018 United States Preventive Services Task Force (USPSTF) draft adjusted the prior opposition to PSA screening. It suggests shared decision-making regarding screening in healthy males 55 to 69 years of age. The final recommendation for that age group states screening should only be done in those who wish it. In those 70 and over, screening remains not recommended.”

The idea here is to screen people who both have a relatively high risk of having prostate cancer and statistically have long enough to live for it to become problematic, but even for that group, screening still isn’t a clear win.

And this is for the USA, where, in general, sending in the cavalry and doing something is preferred over a “wait and see” approach.

abalone16• 6 years ago

Ignoring prostate cancer is in fact a common way to handle it... The technical term for this is "watchful waiting".

That is not watchful waiting. There is a lot of active watching in watchful waiting, not ignoring. For example you may get looked at every 3 months, either a blood test or an TRUS ultrasound, plus a biopsy every couple years. If it gets worse and crosses a threshold, you might get treated.

This is entirely different from just ignoring it. There are many different grades of prostate cancer and the key is detecting the aggressive types before they metastasize.

cell98401794192• 6 years ago

This would be like, high cholesterol may lead to heart disease 5 years from now.. atleast cholesterol can be cut, but yet to start cancer may not be stoppable.

dennis_jeeves2• 6 years ago

Ignoring prostate cancer is in fact a common way to handle it,

Most people find this kind of advise difficult to swallow. Ignoring is equated with negligence, conversely heroic efforts (chemotherapy etc.) is glorified even if most of them produces no appreciable positive outcomes.

raducu2• 6 years ago

I have a SNP (according to ancestry) that gives me ~5X the chance to get prostate cancer. What treatment is available for prostate cancer, besides debilitating surgery?

HeadsUpHigh5• 6 years ago

Chemo and radiotherapy, the whole trifecta. Some new ways of implanting small radioactive disks straight into the prostate with a minimally invasive procedure are being developed as well.

scandox2• 6 years ago

Someone I know had robotic keyhole surgery and they were up and walking about in a week. That was a man in his 60s with mediocre health. He went to the Henry Ford Medical Centre.

pintxo12• 6 years ago

Surgery, done by good surgeons, has low (single digit) complication rates.

Tip: Ask your surgeon how often he does this specific surgery. Removing the prostate requires foremost experience to not severe any nerves surrounding the organ, which are important for potency and continence.

As you would not want your cars brake firmware to be written by someone who usually writes marketing apps, you do not want to get this surgery from anyone who has not specialized on it. There are specialists who do this surgery >200 times a year.

pintxo12• 6 years ago

Depending on personnel preferences, you might want to get a regular PSA check once a year to ensure you catch it early to give you runway to evaluate treatment options. It's better to be able to assess the situation and contact multiple experts than having to rush if detected to late.

vikramkr• 6 years ago

Triple therapy is what a relative of mine underwent after getting Gleeson score 9 (bad but not metastasized) prostrate cancer. He hadn't been doing regulator screenings or would have caught it earlier. The triple therapy (radiation + hormone + brachytherapy, basically little radioactive implants) sucked in terms of side effects at the peak, but it hasn't been long term debilitating, amd he's now doing well in remission.

abalone16• 6 years ago

First, you should be focusing on detection. You probably know about the PSA test and biopsies, but there is also a more sophisticated 4kscore blood test. MRIs and TRUS ultrasounds are also diagnostic tools.

If it’s detected then they will biopsy it and grade the cells to see how aggressive it is. If it’s not aggressive they will just monitor it without treatment.

If it comes to treatment, and you’ve caught it at stage 2 (hasn’t spread), then it’s either cut out your prostate or zap it somehow (e.g. localized radiation).

For “younger” patients they usually recommend surgery. First, with early detection it is less likely to be debilitating. They can spare the nerves that control erectile function, although they can still get messed up and there is still a big chance of some decline in function. But it’s a better outcome than older age brackets or larger tumors — keep that in mind when looking at overall stats.

The reason they recommend surgery is the long term side effects are similar to radiation and if they don’t get it all with surgery, they can go back in and mop up with radiation. Whereas the reverse doesn’t work as well because of tissue damage.

(Note: some people are drawn to alternative ways of zapping it like proton therapy in the hopes it will have less side effects but so far, nothing conclusive.)

Zenst• 6 years ago

That at least was the general topic of the article. The question it raises is interesting: is it sometimes too early to know. reply

Bit like near earth objects, we can detect one far far away and whilst could be 95% sure it will hit, either way, unable to do anything to it until it gets closer. But always good to know ahead of time so can prepare and eventually able to deal with it further out.

abalone16• 6 years ago

I’ve studied this topic a lot and consulted with top prostate cancer centers of excellence. Key points:

- Disregard what you may read about PSA testing / screening being “more harm than good”. This was a relatively recent recommendation in the US by a non specialist task force that is looking to be bad advice. Studies now show it has led to an increase in metastatic cancer.[1] You don’t want that.

- Every man should get their PSA checked by 45, or earlier if it runs in your family. It is a simple blood test. We are lucky to have a tool like that at our disposal; not always the case for other cancers.

- Prostate cancer treatment can have major impacts on quality of life including sexual function. You are much better off getting treated before it reaches stage 3. Quality of life is better. This is not reflected in mortality stats.

- People do die from it and it is a slow and painful death like most cancers. About 2.4% of men die from prostate cancer.[2] With early detection it is very treatable, however, even curable.

- There are advances in screening techniques. PSA is an imperfect but easy and cheap initial screening tool. Doing it early can also establish a baseline. If it’s abnormal it just opens up a conversation and more screening options. Biopsies are also more accurate these days.

Men, go ahead and get your PSA test.

[1] https://jamanetwork.com/journals/jamaoncology/fullarticle/25...

[2] https://www.cancer.org/cancer/prostate-cancer/about/key-stat...

sradman3• 6 years ago

Original paper [1]:

Here we report the preliminary results of PanSeer, a noninvasive blood test based on circulating tumor DNA methylation...

I’m very surprised that parts of the methylome, the per-cell state-machine that controls what genes are transcribed, have sufficient serum concentration to be detected. I suspect that this approach should work for any diseased cell targeted by the immune system as long as the disease results in a small but unique methylation signature.

[1] https://www.nature.com/articles/s41467-020-17316-z

patall3• 6 years ago

With most of these (cell free DNA) assays, its not a single site that you are measuring but a statistical aggregate about profiles that have been defined for a certain cell type. If you know the overall profile of prostate cells and the profile of normal blood, you can subtract the expected profile from a patient sample and the analyse the left-over fraction for whether it is just noise or is matching to one or multiple known cell types.

The surprise from this publication is only that they detect such signatures 4 years earlier than other non-invasive testing. (although nobody in the cfDNA field would be surprised about that).

gww• 6 years ago

There are newer methods that use antibodies to enrich for methylated dna prior to sequencing [1]. The method increases sensitivity as the majority of plasma cfDNA is unmethylated and hematopoietic in origin.

[1] https://www.nature.com/articles/s41586-018-0703-0

sradman3• 6 years ago

gww and patall both point out that this is related to cfDNA [1]:

Circulating free DNA (cfDNA) are degraded DNA fragments released to the blood plasma.

[1] https://en.wikipedia.org/wiki/Circulating_free_DNA

underdeserver• 6 years ago

Breakthrough medicinal research is great, but we should always remember that even most promising results - see the COVID vaccines/treatments we've been hearing about over the past few months - end up not viable at the late stages.

So, cautious optimism, not great hope and sensationalism, is the right attitude to take here.

qayxc• 6 years ago

  “We are still a ways away from having an accurate blood-based ‘pan-cancer’ screening test.
  But it is not impossible to achieve,” Pritchard says.

I think the article itself got you covered there.

kermitje2• 6 years ago

The real false positive rate is much higher than the 5% reported.

The false positive rate reported is ~5% in a sample with an equal number of people that did and did not develop cancer, while the ratio in reality is 1/122 (i.e., 1000 people developed cancer, 122000 did not).

Could still be a useful development, but it does make me wonder about the cost/benefits at this stage.

patall3• 6 years ago

Eventually, this is all about cost. cfDNA assays are targetted to in the end cost less than 100 bucks per sample which for the detection of a single cancer puts you in the range of $12000 for one tumor diagnosis. Ideally, you can now decrease the therapy cost of that one diagnosis while also boosting survival chances. And $12000 is not much in tumor therapy.

The key however here is the advanced prognosis that may allow totally different therapeutic approaches, extend the understanding risk factors etc. and the fact that you do not need to have a specialist on side, taking a blood sample can in principle be done at home and the rest is automatic.

Edit: Oh, and 5% false positives is not that bad actually, I do not have numbers is my head but would expect other essays like breast cancer screening to be also in that range.

helsinkiandrew• 6 years ago

5% false positives on people who have some symptoms of cancer isn’t bad. But 5% of a ‘high risk group’ could be a lot - particularly if the cancer is too early to confirm detection any other way yet and possibly not treatable for several years.

4886436895• 6 years ago

The problem is with breast cancer screening the next step probably isn't a full body CT. If you detect cancer in the blood, next step would be actually finding it. A full body CT would actually increase your cancer risk and add the chances for another false positive which might involve more invasive diagnosis. The real risk/benefit calculations quickly become tricky.

All that said, I'd rather risk dying while propofol'ed, than from say colon cancer. I mean all this is about how we die, not if we have to die.

HeadsUpHigh5• 6 years ago

If you need 12k$ for a single tumor diagnosis, then we should consider MRI imaging. Those cost significantly less than that. And as of right now, the positive effects of chemotherapy on such early cancers would be debatable. Still a useful development though.

noknownsender2• 6 years ago

Another potential benefit of this sort of early detection would be the ability to more effectively test interventions that might have little effect on more advanced cancers.

That could help direct research into the development of cancers at its earliest stages, and potentially pave the way for more effective prevention.

blablabla123• 6 years ago

Blood tests for testing cancer markers during therapy are already standard since a long time. A family member of mine got that testing regularly about 10 years ago but the predictive value was not good. Still, if the accuracy improves it's a good development and could be revolutionary once high enough since some types of cancer are very likely to be curable if detected early enough. But yes, a false positive result can make things worse, especially for people that are in a risk group.

edwhitesell• 6 years ago

but the predictive value was not good

My understanding is that there is some dependency on the type of cancer, but mostly it depends on your immune system response. Doctors are pretty clear that just having a cold can affect the numbers.

blago• 6 years ago

Maybe it can be used as a component/signal in a broader basket of diagnostic tests and symptoms?

mrfusion• 6 years ago

Could you take it multiple times to help? Or it could be a guide to what additional screening you do?

DangerousPie4• 6 years ago

That would only help if the false positive occur completely at random. If the error is systematic (for example because the test is detecting something else in the blood) you'd just keep getting false positives.

noknownsender2• 6 years ago

It probably depends on what is causing the false positive.

If it is just some variance in the test, then multiple testings could help (And the test could probably be improved to reduce false positives pretty easily)

But if there is something intrinsic to those tested (say, some hormone level or other) Repeat tests will give repeat false positives. AND it may be harder to eliminate false positives by refining the test

DangerousPie4• 6 years ago

The false positive rate doesn't depend on the number of true positives in the population. However, as you rightly point out the metric that actually matters for these kinds of screening is the precision/positive predictive value, and that one does.

Beltiras• 6 years ago

96% specificity. That's really good for a screening test.

joshgel3• 6 years ago

Yes, this is right.

But, the even more important metric to measure is mortality. Detecting a cancer that is 100% fatal 1 day earlier than traditional tests obviously wouldn't be that impressive. Even if the PPV is very high.

It's also very possible that a cancer that is detected accurately 6 months earlier, but that detection still doesn't improve our ability to treat the cancer. In these cases, it might even look like mortality is improved if you measure time from detection to death ("early detection extended survival by 6 months"). But, actually, it didn't change much.

So, that's all to say that the "Experimental" in the title should temper expectations considerably, because that has real meaning.

kermitje2• 6 years ago

Ah indeed, I was wrong. You will get approximately 6 false positives for every true positive.

Unfortunately I can't edit my comment anymore.

abcc83• 6 years ago

Yes, the positive predictive value of the test may be low, with the PPV being equal to the number of true positives divide by the number of true positives plus the number of false positives.

Since this test is designed to identify cancer very early, a likely solution to the low PPV problem would be to re-test the individual, perhaps even multiple times. The likelihood of multiple consecutive FP test results, barring a biological reason for the FP, would at some point warrant a more accurate test, be it a screen or diagnostic test depending on tumor type. Also keep in mind that the PPV of the test would increase with a person's age - an 80 year old is at a greater risk of developing cancer than is a 30 year old. This test would also be useful for people with hereditary cancer syndromes.

The cost benefit would be huge - imagine if everyone could identify their cancer 6 months or even years earlier. Mortality would greatly decrease, as would spending on treatments, etc.

mbreese• 6 years ago

The cost benefit for someone with a cancer diagnosis could be huge. But for the people with false positives, that could also be very harmful to people. A (false) cancer diagnosis would be incredibly stressful.

It’s tricky to find that balance.

hcknwscommenter• 6 years ago

"barring a biological reason for the FP"

I think that's an unwarranted assumption. Sure, another source of false positives is contamination or user error even, but other than that most FP are indeed due to a (usually unknown) biological reason. I'm reminded of a friend that was just positive she was not pregnant. She tested herself three times with three different pee stick brands. She was wrong. They all use the same chemistry, and for some reason something in her body interferes with those tests.

m463• 6 years ago

Personally I'd like to know I'm in really early stages.

I would take positive steps waiting for a retest, such as cutting out refined carbs, saunas or other heat therapies, and eliminating stress and other harmful situations.

false positive? probably still a better lifestyle will have it's own benefits.

(IMHO)

billpg• 6 years ago

We call it the "Do I qualify for health insurance?" test.

civil_engineer• 6 years ago

If false positive rate is 5%, and 1000 of 123,000 were diagnosed with cancer over 10 years, this test would produce 6,100 false positives, and 1,000 true positives.

Six out of seven positive tests would be false positives.

whichquestion• 6 years ago

Would having 6000 false positives be okay for being able to find the 1000 true positives?

Would further testing be able to show whether or not there is actually cancer?

Maybe they will be able to improve the accuracy of the test enough where the false positive rate of the test is <<5%...

TeaDrunk• 6 years ago

It also means that the test fails at detecting cancer more often than not, and will mean that if it detects a true cancer this time doctors will be inclined to not take it seriously because evidence/experience is that the test is useless

mtts• 6 years ago

Would having 6000 false positives be okay for being able to find the 1000 true positives?

I’d say no. That’s 5000 people who are told they might have cancer while in fact they don’t and who will then undergo further testing that is at best traumatic and at worst extremely invasive if not outright damaging.

Take intestinal cancer, for example. You can get screened for that and if you screen positive, they will take a biopsy - a fairly unpleasant and not entirely risk free procedure. Then it gets worse. If the biopsy shows some part of your intestines isn’t quite in order (a likely outcome, though not necessarily one that indicates cancer) they will take out that bit of intestine, just to be safe. This is a very invasive procedure and because it’s your intestines we’re talking about, you digestive system will be seriously out of whack for a while - if it ever heals completely - seriously and significantly degrading your quality of life. All this for a, let’s use your figures, 1 in 6 chance that you might have had cancer.

cactus2093• 6 years ago

And one out of seven is a true positive, whereas overall 1 in 123 people developed cancer. So a positive result on this test still means you are 17.5x more likely to develop cancer than the average person in this group if they were never tested.

It's weird to pretend like this is not significant new information, which has the potential save lives. Whether or not we have an acceptably safe way today to act on this early information is a separate question, this is one more tool that can be used in improving treatments.

cell98401794192• 6 years ago

Call me silly, but, methylation is a hallmark of aging as well. So all cancer patients would show methylation, but all methylation will not indicate cancer. If that were the case, cancer would be the only cause of natual death.

DangerousPie4• 6 years ago

That's not what the test is doing. They are looking at methylation in specific places.

mchusma• 6 years ago

A good econ talk on why this kind of thing (improving cancer diagnostics) is by far the most promising "cure for cancer".

http://www.econtalk.org/azra-raza-on-the-first-cell/

I hope we have many more tests like this that can be done frequently and add to the arsenal. Great work to these researchers.

ramidarigaz• 6 years ago

Azra Raza was also on the Mindscape podcast, really realy good interview.

https://www.preposterousuniverse.com/podcast/2019/12/16/77-a...

Cirpop• 6 years ago

Interesting, especially considering pancreatic cancer. That one can be treated if caught early on, but it hardly ever is, making it incredibly lethal, even for a cancer to be.

TaupeRanger• 6 years ago

Guess it's time to share this again. "Cancer screening has never been shown to save lives" - Oncologist Vinay Prasad. Detection is not the problem. It's what to do once you find it. Iatrogenic harms are real.

https://www.bmj.com/content/352/bmj.h6080

With better testing, we might be able to save some people, but we might also be subjecting a great deal more people to harms through unnecessary treatment and psychological trauma.

jforman• 6 years ago

You can't design interventions for problems that you cannot see. Detection alone doesn't save lives, but it is a necessary step to the discovery of interventions that do.

eloff• 6 years ago

There's a lot to this, if you look hard enough you'll find something wrong. But that something wrong probably would have never progressed into something that kills you - however the interventions you then undergo are not without risk. Like if you have the slow-growing prostate cancer, you'll die of something else. But if you operate you're taking risks of surgery and lifetime incontinence, and might spread it elsewhere in the body.

However, I still think early detection is an important first step to finding better interventions. Once you know it's there you can start to come up with less risky/invasive treatments. The odds of dealing with it at an early stage are so much better and the scope of the intervention required so much smaller.

jliptzin• 6 years ago

Cures and vaccines would be great but I feel like we are missing an opportunity with improved testing not just for cancer but also for infectious diseases. Imagine a toilet that can detect a UTI/STI or parasite or a monitor in my room that can detect airborne viral particles which might tell me I have a cold, flu or COVID before I even know about it. Then I know to treat and isolate before spreading it to others.

If we had cheap, instant, accurate tests for infectious diseases then I’d imagine we could begin eradicating some of them.

vondur• 6 years ago

Seems really cool, but how many cancers progress from something minor to something life threatening? Some of the treatments can be pretty invasive/lot's of side effects. I wonder how much cancer the body can deal with on it's own and never progresses?

rsync• 6 years ago

If you care even the smallest amount about your own, personal, cancer risk you should immediately cut your feeding window to 8 (or even 6) hours per day and start walking a few miles, daily.

I did not mention "fasting" or "diet" or "weight loss".

Just condense your caloric input into a tighter window and walk more than zero miles per day.

It's silly to pursue fine grained, specific optimizations when the juiciest, lowest hanging fruit is stubbornly, inexplicably, left unpicked.

wonderlg• 6 years ago

Source? There’s so much information about nutrition online that one should not just trust the first comment found on a forum.

Edit: I’m referring to the “feeding window”

waterhouse4• 6 years ago

I think the common term is "intermittent fasting" (despite the protest about the word "fasting"), which covers a range of strategies—"time-restricted feeding" is the type where the fasting period is less than a day. https://en.wikipedia.org/wiki/Intermittent_fasting#Types

There is at least some research supporting the claim that time-restricted feeding inhibits the growth of cancer in humans: "In repeated-measures Cox proportional hazards regression models, fasting less than 13 hours per night (lower 2 tertiles of nightly fasting distribution) was associated with an increase in the risk of breast cancer recurrence compared with fasting 13 or more hours per night (hazard ratio, 1.36; 95% CI, 1.05-1.76)." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982776/

There have also been studies in mice: "Results and Conclusion: TRF had a dramatic effect, reducing tumor growth in obese mice fed a high fat diet (HFD) to levels seen in lean mice. Tumor growth and initiation was also delayed in the transgenic PyMT model of mammary tumorigenesis. Our results further suggest that the antitumor effect of TRF is at least partially mediated by reducing hyperinsulinemia, suggesting that this intervention may be effective in breast cancer prevention and therapy." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6552025/

Balgair• 6 years ago

To be clear here: these are only circulating cancers. Cancers that break through mesenchymal barriers or can affect the blood are not very common. It's great, amazing even, if you can catch them. But many cancers will never show up in the blood. Still, great work!

Experimental blood test detects cancer up to four years before symptoms appear

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