
The Dark Side of Early Diagnosis - DanBC
https://www.prospectmagazine.co.uk/magazine/early-diagnosis-cancer-screening-women-risk
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andrewla
There are two main statistical errors touched on in the article. One is that
metrics like 5-year survivability are heavily skewed by early detection, even
in the placebo case. The other is that false positives in early detection can
skew the numbers on effectiveness of treatment, even when the treatment is a
placebo.

In cases where the treatment or the screening itself has negative effects,
this is thrown into even more confusion, because the screening/treatment combo
may actually have net negative effects, but those effects are impossible to
measure without experimental data -- i.e. giving the treatment (blindly) to
some people who have not been screened or who passed the screening, and
withholding it (blindly) from some who failed the screening.

Ethical obligations of medical practitioners essentially prevent us from
leaving things untreated when the risk of harm is considered reasonable, so
those experiments are very hard to carry out.

Recently (4-5 years ago?) there was a change to the CPR protocols used by US
paramedics and ERs. How they managed this is beyond me. Since CPR is a
procedure that people perceive as having a higher rate of success than it does
in reality, how would you like to be the paramedic that says "your spouse is
dead, and also, by the way, on an completely unrelated note, we used an
alternative method of CPR, but that probably had nothing to do with their
death".

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barking
I'd never looked at it this way before but it makes sense. You'd have thought
that accounting for the extent of a cancer at diagnosis would be a requirement
for determining the success of any subsequent treatment.

Is it cynical to assume that a lot of medical research is next to worthless,
done almost as a box ticking exercise. Do research to get a paper published to
put on your resume. And a lot more is done by/for pharmaceutical companies who
have an interest in their drug been shown in a good light.

~~~
oderi
I'd call that overly cynical, yes. Not the point about the pharm companies -
seems that a big portion of physicians I've talked to pretty much outright
disregard results from trials run by them. Even in unbiased trials, however,
the struggle between sample sizes/statistical robustness and getting new
potentially life-saving treatments out into the real world in a timely manner
is real.

~~~
barking
You could be right. The reason I said it was that as part of the pathway to
becoming a senior hospital doctor (apart from moving a lot, working hard and
studying for post-graduate exams) is the requirement to get stuff published.
This makes a lot of doctors do research who aren't interested in a career in
research. If that was me I'd be tempted to do something that was as easy as
possible to get that box ticked.

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jaclaz
In the "negative" example (non curable cancer) there is a huge difference:

1) living from 62 to 66 blissfully unaware of it (and thus at least living
peacefully these 4 years)

2) living from 62 to 66 in a extremely preoccupied status and possibly with
the side effets of the (ending up as ineffective) cures

Though in many cases of non-early diagnosis there is the "regret" about "if it
had been diagnosed earlier then it would have been probably curable" which may
(or may not) be an aggravation of the quality of life in the last 4 years
(66-70).

Tough to say what is better for the unfortunate patient.

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bigmit37
This was eye opening. I was always under the impression that early detection
would mean a different stage of cancer.

