111–120 of 290 posts
I pay an extra $60 a year to have my ophthalmologist take a digital image of my retina. It comes back as normal every year, but if something does change we can diff the image against the baseline. Maybe I don't want to look for cancer right now but if I spend $1,000 every 5 years to take an image for later use... isn't that useful?
Er wait is retinal cancer a thing?
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer So that would be 1.71% of people getting a full body MRI catching cancer early. That seems like an astoundingly good return to me. What does late cancer treatment and lost lives cost? Many times these MRI’s. If everyone did this, would there be any significant number of l…
Earlier quoted context omitted.
No. When there is low prevalence of a condition, but a non-zero false positive rate of a test, the false positives generated by universal testing can in fact be a net dis-benefit (worry, invasive further procedures, etc) to the patient population as a whole, regardless of cost. This is a well understood statistical phenomenon, and is carefully considered by healthcare systems when advising on testing.
Read my #2 option, which accounts for that
What if in reality the doctors can only say if the probability is above 60% or not? What if some doctors are better than others at estimating probabilities? What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
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> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, These treatments are wonderful and it is great that they exist. But many people fail to understand the difference in terms of pretest probability, etc. I can absolutely see the heavy psychological impact pending biopsy results may have. People are quick to discount these issues when you raise them as a concern, but…
I have multiple scans a year. "Scanxiety" is real.
Can someone ELI5 why false positives on a MRI are so bad? From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight. At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups? I get that ideally we'd have a crystal ball with 0 type I / type II erro…
https://www.bbc.com/news/articles/cm20169gz44o.amp
This seems super dumb to me. If the test detects cancer that doesn't need treatment, don't treat it!! It's still better to know it's there and that you need to monitor it.
> Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time,
Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
Earlier quoted context omitted.
Read my #2 option, which accounts for that
As if there was an easy, foolproof and precise way to calculate these probabilities. "Just only alter the patient when it is appropriate" he said. You can solve all the world's problems this way, just "always do the right thing". Reality, unfortunately, is more complicated. What if in reality the doctors can only say if the probability is above 60% or not? What if some doctors are better than others at estimating pro…
It's this one
It doesn't matter that some cancers are hard to diagnose. What matters is that some are not hard, especially if you have multiple scans spanning several years
Did you know optometrists now scan your retina during ordinary eyeglasses appointments? They didn't do this in the past because it was too expensive. But optometrists cannot diagnose or treat based on these scans. They refer you to an opthamologist.
Some day your PCP will do the same with MRIs, but only once they are cheap. For now only rich people have this luxury
Can someone ELI5 why false positives on a MRI are so bad? From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight. At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups? I get that ideally we'd have a crystal ball with 0 type I / type II erro…
Earlier quoted context omitted.
… they do it based on the scan result. Avoiding a biopsy that wasn’t needed is a good thing.
You're imagining that the doctor is required to act irrationally or against the patient's interest. I understand that they do act this way, but I'm pointing out that they don't have to! You walk into a doctor's office and meet for the first time. Case 1. You have 3 full body MRIs taken 6 months apart in hand and give them to your doctor. Nobody has opened or looked at the scans yet. Case 2. You do not have a scan yet…
Case 1 without cancer: you're a guy that knows more than doctors because you're the "I have 3 scans on hand guy", so as soon as you open the scans and the doctor says there's a mass, you will say 'OK what can we do???' And then you had a worthless biopsy.
Case 1 with cancer: you saved the 1 week it would take to schedule the new scan and get results and you're basically in the same situation except one week earlier.
Earlier quoted context omitted.
You're imagining that the doctor is required to act irrationally or against the patient's interest. I understand that they do act this way, but I'm pointing out that they don't have to! You walk into a doctor's office and meet for the first time. Case 1. You have 3 full body MRIs taken 6 months apart in hand and give them to your doctor. Nobody has opened or looked at the scans yet. Case 2. You do not have a scan yet…
You a-priori do not know if you have cancer. The case 1 branches are: Case 1 without cancer: you're a guy that knows more than doctors because you're the "I have 3 scans on hand guy", so as soon as you open the scans and the doctor says there's a mass, you will say 'OK what can we do???' And then you had a worthless biopsy. Case 1 with cancer: you saved the 1 week it would take to schedule the new scan and get result…
And for the first part that doesn't happen in my scenario before the doctor doesn't look at the scans