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.
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.)
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
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.
https://www.healthcare.gov/coverage/preventive-care-benefits...
https://www.uspreventiveservicestaskforce.org/uspstf/recomme...
The recommendations tend to take these into account, and then you and your doctor adjust.
Sometimes politics gets into it, like with the recent changes to breast cancer recommendations, but, overall, it works well for many people.
For instance, prostate cancer blood screening often led to radical treatments that are no longer thought to be worth it for most people.
> most prostate cancer grows so slowly, if it grows at all, that other illnesses are likely to prove lethal first
https://www.nytimes.com/2023/05/08/health/prostate-cancer-sc...
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.
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.
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.
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.
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%.
Could you elaborate on this?
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.
I'd assume the chances of getting a second false positive if you already got one are much higher.
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?
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
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.
Prevalence of breast cancer: 1%
Sensitivity (percent of people who have the disease test positive): 90%
Specificity (percent of people without the disease test negative): 91%
And asked, "How many people who test positive have the disease?" (i.e., positive predictive value)
It's only 1/11. I think only 20% got it right (in a 4 answer multiple choice question)
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%".
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)
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.
(Not a doctor just surrounded by them)
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".
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.
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.
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.
It was something like 300ml of blood spread over ~40 vials. They tried to charge me $7500.
It did lead to a diagnosis.
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.