Posted by Michael Gilligan on 15/09/2022 00:18:37:
I recently did a Bowel Cancer screening test … Obvious conclusion being that it’s not worth testing people over 74
MichaelG.
Well, you've certainly opened a can of worms. The obvious response is, "Not worth it to whom by testing people over 74?" Clearly, the individual may think it's worth a lot, but the funding organisation may consider that, for each life saved, the cost per added year of life, plus the treatment cost, plus the added pension payouts, etc. isn't good financial value. The purely medical aguments around screening programmes are complex enough, without considering finance and politics.
To illustrate some of the problems around screening, a screening programme is only appropriate if it causes an acceptably small amount of harm, AND if the disease's natural history is known, so that it has been established that early diagnosis increases survival significantly, AND if there is effective treatment, AND if the disease is 'sufficiently' prevalent in the screened population, AND if the performance of the screening test(s) is (are) good enough. (Capitalised AND to indicate logical AND). This onerous requirement makes prostate screening rather dubiously beneficial to the population, mainly because treatment often causes significant disruption to a symptomless individual, and lots of old men die with cancer cells in their prostate, but not from the disease.
Another problem is that, if the prevalence of a screened-for disease is low (most are), and the screening test is not very, very nearly perfect (none are), the maths generally results in the number of false positives and/or false negatives significantly exceeding the number of true positive diagnoses. This isn't because of medical failings, it's just maths.
If you are found to have a condition predisposing to colonic malignancy (some inflammatory bowel diseases, polyposis coli, etc.), one would hope that you would be offered life-time screening, even by the creaking NHS. And, if you were not, paying for it might be medically wise, but financially a difficult decision.