There seems to be a ton of benefits to doing all kinds of blood work - from vitamin deficiencies, hormonal changes, cancer signs, etc. Our system is very reactionary in that we order all these tests AFTER we get sick.
Why is there not a more proactive approach to getting bloodwork done with as many tests as possible? We should see this type of service like going to the dentist.
Say that this test has a false positive 1 in 1000 times. If you test 100,000 people, you'll get 100 positives that need invasive further testing and followup, and 5 real pancreatic cancer cases.
Society will pay for 100,000 tests, and 105 cases of followup. You may cause lasting harm to some of those 105 people. And then it's not clear if you can improve the survival of the 5 pancreatic cancer cases much. They'll live longer after diagnosis (because you diagnosed earlier) but not necessarily longer overall.
(One other screening effect: You'll find more "real cancer" that is so slow growing that it may have always remained subclinical before the more sensitive testing; And the most serious cancers, you won't find so much sooner, because they grow so much in the interval between tests.)
> In the case of pancreatic cancer, it is much more aggressive and you need to catch it early.
It's not clear that the cancers that you would find early with a more sensitive test are those more aggressive cancers.
The pancreatic cancers we find with our current detection (generally after becoming symptomatic) are typically quite aggressive. But are they all the cancers? Likewise, if the cancer is aggressive, it can grow quite a bit between screening intervals and not be found all that early.
(Part of why we think that "finding cancer early" is such a benefit is that because the smaller/earlier cancers we find are less aggressive than the cancers that we first find when they're huge and spread. There is definitely an effect from earlier detection but our estimate of it has been confused by this effect.)
As we've increased cancer screening, we've found that survival rates have gone up, as have survival times after detection... but unfortunately we've often also found that the screening doesn't always reduce the number of people dying of that cancer at a certain age. Instead, you find more cancers, and you find them earlier so more people live to 5 years, even if you've changed nothing. Cancer treatment has gotten better, but most of the benefits we have expected from better cancer screening have not materialized.
Finding pancreatic cancer early sounds good. And it may be able to reduce mortality from pancreatic cancer, but it's not a sure thing.
My grandfather (a doctor) always used to say this. There’s also an aggressive fast growing kind of prostate cancer, but treatment basically does nothing for survival rates (or at least that was the case decades ago when he was practicing.)
So his advice was, don’t look, don’t treat. Either you have the slow one and treatment is harmful, or you have the fast one and you’re going to die soon anyway.
Your grandfather's take has become increasingly accepted for prostate cancer. There is more of a watch and see attitude to make sure that the patient doesn't have a rare case of aggressive growth.
As you mentioned, the outcomes aren't significantly different, regardless of how you treat it.
From the article linked above:
> Researchers followed more than 1,600 men with localized prostate cancer who, from 1999 to 2009, received what they called active monitoring, a prostatectomy or radiation with hormone therapy.
Over an exceptionally long follow-up averaging 15 years, fewer than 3 percent of the men, whose average age at diagnosis was 62, had died of prostate cancer. The differences between the three treatment groups were not statistically significant.
> You can just run test multiple times to eradicate this possibility
The measurements are not independent and the quality of the measurement is not improved by this.
> you can confirm it with another method.
Yes. And usually the other method is invasive and expensive and bears some risk.
And then you get results like the blood test saying "very likely cancer" and the biopsy saying "uh, probably not?" that you need to decide what to do with.
I'm confused. If this blood test gave a false positive that wasn't due to an anomaly in the blood itself, then why can't we assume that the likelihood of getting a false positive twice is lower than getting it once?
> I'm confused. If this blood test gave a false positive that wasn't due to an anomaly in the blood itself,
That's the errant part. A small amount of the false positives will be because of lab issues. The rest will be because this patient is different in some way, but not all of them are cancer. Medicine doesn't have very many perfectly specific tests.
So you have a patient who has some weird enzymes around because they're genetically different, for example, and they always pop positive on this particular test. Or has an unusual diet that causes some other non-tested-for-enzyme level to be high enough to set off this sensor. Or whatever.
In this case, the specificity is 98%, so this false positive rate is about 2%.
Yah, I'm well familiar with the base rate fallacy and I still catch myself screwing it up. It's so unintuitive. I use mental math a lot to counter my intuition.
If sensitivity is high and the base rate is low, you can approximate it with .01 / (1-.91).
Or, mental math assuming 10,000 people is not unreasonable for your case (100 with disease, 90 true positives; 9900 * 9/100 false positives.. divide everything by 9 to make it easier, 10 true positives and 99 false positives, or 10/109 or say "9%".
You are assuming that those false positive rates are fixed, but they aren't. The "positive" criteria are done by an analysis exactly as sophisticated as a human scanning a list of numbers. The process is a joke and it needs to be improved by more data and better analysis, not this nonsensical "don't test people because they might be positive" argument.
No, I'm assuming there's a tradeoff between sensitivity (spotting cancers) and specificity (having your positive results actually be cancer).
ANOVA to pick variables and then reasonably selecting thresholds is a fine process that avoids overfit.
The big problem is, biology is messy and measuring lots of people to find correct thresholds is really expensive and time consuming. It's not really a technological problem, though technology has helped a little.
you will do surgery on some of the 105 people. Some of them might die from complications, infections, etc or at least have lasting damage. Since several of the 5 people will not be any better off with treatment it's entirely possible that the screening produces palpably worse outcome.
The earlier you screen, the worse this is, since the ratio of false positives vs true positives gets higher and higher, for example 1000 vs 5 or 10000 vs 5.
It's also psychologically harmful to have the positive test hanging over your head. I'm nearing the age where doctors start harassing about colonoscopies. You can do an at-home test instead of the full procedure, and it has a very good chance of ruling out the need for a colonoscopy. But it also has a high false positive rate; there's a decent chance that you'll end up in a state of "need a colonoscopy, also a colon cancer screener flagged you". I'm dreading the colonoscopy prep, but I'm not doing the at-home thing.
I've been scoped twice and the prep sucks. It's shitting your ass out for half a day. On the positive side, getting sedated isn't half bad and you get the day off work.
And if you aren’t a fan of being sedated (I’ve never been, and I’d prefer to keep it that way), you can opt to do it without sedation. Had a colonoscopy and an upper endoscopy the same day, no sedation. A little uncomfy, but not painful. If you can push yourself through hard weight training sets, or run a 50k, or anything else that entails a bit of discomfort, a colonoscopy is no biggy.
I'm another one who's had two colonoscopies. Try to schedule it for the morning so that most of the fasting time will be while you're asleep. The prep is not a lot of fun, but it's only about half a day and it's very much not as bad as gastroenteritis or anything else that'll give you a good bout of diarrhoea.
Then let's take those things into account when calculating what tests to do. Surely, though, we can do better as a society than solving this with "no preemptive testing except for extreme risks".
There's a ton of research and regulatory oversight in this area, and the choices made generally make sense. You can safely assume that the testing recommendations are 3-5 years behind the research, though.
The US Preventive Services Task Force (USPSTF) is the body doing that meta-analysis and writing recommendations. The recommendations are for general patients (high-risk patients should be identified and guided by their doctors), and are based on how much the screening/prevention will extend or improve patients' lives. The USPSTF explicitly does not consider monetary cost.
We haven't even solved the most basic shit like shelter, food, education, &c for millions of people in the west, as a society we're faaaaaaaaar from universal yearly full health checkups. As an individual feel free to get private checks, they'll gladly take your money
The fact that there are huge costs in the USA to even periodic medical checkups has severely impacted longevity in the USA to the point it ranks close to Cuba in longevity. Those with a health plan are close to the highest ranked nations. The poor without a plan at all are around ~4-5 less long lived. There is a nice rabbit hole in this data.
https://www.google.com/search?q=longevity+charts&rlz=1C1CHZN...
This has a huge GDP cost in the USA, that needs to be addressed.
The causes are big pharma/hospo/AMA/insuro/lobbyo....
One wonders why the AMA is there? - they limit the numbers of doctors trained in Universities/training hospitals to forestall price competition among doctors by various means. Dentists do the same.
There is no proven health benefit to periodic medical checkups for healthy adults. At the population level it's a waste of resources. But certain preventive screening services are covered at no cost to the patient because they've been shown to be effective through high quality research studies.
Cost of a yearly checkup should be "taken care of", because Obamacare mandated free annual checkups, as long as you don't accidentally trigger any other billing codes while you're there. But, regardless of cost, there's a shortage of providers, so it's hard to schedule the checkup. And there's still a lot of uninsured people out there.
For better or worse, under the American healthcare system, the patient pays for those tests, sometimes covered by insurance. If the tests are paid for out of pocket by the patient, is there still such issue?
The economic argument doesn't change whether it's a private cost or purely a social cost (private costs are included in social costs, since private expenditures are part of society's expenditures).
I think the issue is exactly the same no matter who pays.
To reframe it from the individual patient's perspective, when you take a test simply for the sake of screening, there is the chance you'll learn something true that helps you, and the chance you will learn something false that hurts you
I was the tech lead at a YC company doing exactly this (Spot Health, W22) until a little while ago. There's a ton of very hopeful things happening in the industry behind the scenes. Insurance via employee benefit schemes is the lever to drive this into people's lives.
The industry refers to this as gap closure - care gaps are instances of a patient not receiving care when they should have. For example, not getting treatment for stage 1 cancer because you didn't have a checkup is a care gap.
Insurance companies are very incentivised to close care gaps because it results in cheaper premiums. Incentives between health insurance and patients are often not aligned (as we've seen in the news recently), but this is one case where they are radically incentivised to offer additional diagnostics if it results in fewer costly payouts for severe illnesses that come later.
In the medium term, the cost of full genome sequencing is quietly experiencing a 10x decrease in cost. Within a decade, I expect it to be the norm that all people are fully genetically sequenced and for the correlations enabled by that dataset to have made the value of being sequenced 10x. So probably a 100x increase or so in the value of genome sequencing over the next few years.
(Also, before anyone says it, yes 23&Me should feel very very ashamed for the deanonymised patient record data breaches they've experienced. The whole industry needs a slap in the face when it comes to privacy)
I guess after ~30 years past grad school in the software industry, having had high hopes for the internet and everything back in the 90s, I'm way too cynical.
This won't be used to "close the care gap", unless they can charge more $$ for the additional checkups than they'll expect to have to give out in care as a result.
And they'll drop anyone suspected of needing too much care in the future based on their genome, even if they aren't sick. Pre-existing conditions times 100 (you know they'll be re-instated by the current administration soon enough).
e.g. 17% of the people with that gene had cancer, and you have it, so raise your rates 151%. Oh wait, 37% of the people with this other gene had dementia - you're no longer covered.
Eventually, they'll only accept those people with a genomic lifetime 90% profit profile. That's the way this sort of thing works in the "real" world.
Despite how much we know in medicine we still know too little. Bloodwork will give you a snapshot of that persons blood chemistry. It’s still up to the doctor and lab to put together what that composition means. In other words, if there is too much iron in the blood there could be x number of reasons for that. Most might be benign, and a small handful could be life threatening.
Theranos tried the "move fast and test blood" approach. Maybe one of the existing testing companies can find a more balanced approach in the current environment.
Theranos’ specific claim was that they could do existing tests with way less blood and way less cost. One of the ways they kept their fraud under wraps was to simply do the tests the old way behind the scenes.
So, blood tests in general were not the controversial part of Theranos.
As others have pointed out, the obstacles to large scale prophylactic blood testing are false positives, and general resistance of health insurers to fund anything not strictly reacting to disease or injury.
Widespread pre-emptive testing was not what Theranos tried. Defrauding investors that the technology existed for widespread, inexpensive pre-emptive testing even at small scale is what Theranos tried.
There is almost certainly gold in them hills if you dig deep enough and survey systematically enough, but Theranos started with precise coordinates, claiming they'd "found it", and demanded investors for a mine, while privately they were thinking "If we don't find it on the surface, who cares, we got paid, this is how VC works".
It probably all comes down to cost. I remember reading studies about widespread melanoma screening and they were writing things that basically amounted to: "overall it adds ~0.5 day of life expectancy to the average Joe, based on costs &co it's worth it if you consider 1 year of human life worth $30k"
I find that doctors are very resistant to ordering blood tests. I often get responses saying it isn’t necessary or whatever. I feel patients should be entitled to whatever diagnostics they demand. I don’t know why doctors are even needed to get that done. Other than the scam of insurance coverage of course.
For me (eu) the dentist is pricy but these tests are included in public and private; i can ask my doctor any time and i get them, including for markers. Dentist costs, I do it every 6 months, but most people i know maybe once every few years.
I definitely prefer doing the testing myself instead of begging the doctor to order things.
About the only time I go to doctors is to beg for antibiotics- which they often refuse to give me. They say, "oh, it's probably a virus." Okay, but all of the virus tests I can find came back negative. I have a CBC showing elevated WBC. Coughing up yellow-green slime. Can you order a sputum culture for me? "no, come back if you are still sick after 10 days". Great, $200 and 30 minutes in the waiting room getting exposed to other sickos for nothing, miss another week of work. The gatekeeping of medical care infuriates me. I have plenty of money, let me use it to get better faster.
Yes but that blood work checks things like cholesterol and vitamin deficiencies. They aren't checking for these types of markers that point toward cancers. They may notice something is out of whack that may lead to more specific testing but I think the overall question is why aren't we just checking for everything more frequently with these blood draws?
I had to explicitly ask for Vit D and Iron/Ferritin to be added to the default bunch of tests on my decennial check-up as I was constantly tired. They eventually found out I had iron-deficient anaemia caused by undiagnosed Coeliac disease.
It's very important to advocate for yourself at the doctor.
My wife went to the doctor many times complaining about fatigue. Response: "Oh, you're unemployed, you must be just bored...".
We moved, new doctor, new yearly checkup, and one attentive doctor noticed something on her. 6 months and a whole battery of tests later she got a diagnosis of EDS. A genetic disease that causes issues with connective tissue.
She was always tired because her muscles were compensating in places where people who have normal connective tissue can rely on this tissue as a stabilizer.
I'm very glad that you were able to get your diagnosis.
The amount of blood drawn isn't enough to run all of these tests at once. They would need to multiple blood draws for tests that in most cases will end up being unnecessary.
It's unnecessary until it finds something. My doctor is pretty thorough and I will give 3 vials with my yearly physical bloodwork. I get a pretty comprehensive set of results but my grandfather died of pancreatic cancer and I'd love for this to be included in that testing.
Depends on the country you live in. There are countries that don't do them with similar health results as countries that do them.
There is a stereotype that Dutch doctors will prescribe paracetamol for anything because they are really defensive with medication and doctor visits and the result is generally the same as countries that do check ups.
Yes, but insurance does not cover large amounts of screening tests. Last year my A1C check was not covered. In North Carolina my wife's vitamin D test is not covered by her primary or gyno for routine checks.
Why is there not a more proactive approach to getting bloodwork done with as many tests as possible? We should see this type of service like going to the dentist.
Seems like a good industry to disrupt.