This is only about screening the asymptomatic in the screening programme. Not about people in other age groups requesting screens, or diagnosing symptoms people find themselves, or those at high risk. Only the screening programme.
Anecdotes don’t make science. Overdiagnosis is found through statistics - comparing screened with unscreened populations and finding cancer incidence higher in screened populations, without corresponding decrease in advanced cancer incidence years after screening is introduced, less than hoped for reduction in deaths from breast cancer (if any) and in deaths from all causes in the two groups.
Interpretation: screening detects cancers (noninvasive and invasive) which would never progress; not all cancers kill. Combined with what is known from cervical, prostate, lung cancer (they did try screening the at-risk from lung cancer and abandoned it due to overtreatment; same for babies with neuroblastoma in Japan), other cancers and autopsy studies, it is known many people have cancerous changes in their bodies which never progress to cause harm. Cancer isn’t as simple as you think. It can grow slowly (very), clear itself, stay as it is or take off like a rocket. They don’t know enough in many cases to know “what would have happened if…”
If you are screened you risk finding these. If it was rare you might think it worth the risk. If more common you might pause. People react differently and they have a right to make up their own minds. Partly it depends on the treatment: if the treatment was a pill we’d all go for it. The Nordic Cochrane Centre, which exists for the purpose of examining all available evidence about interventions to get the best overview of effectiveness, estimates that about 50% screen-detected cancers would not have progressed. The NHS figure is 5-10%, but not in the leaflets, not in that form on their website. I’m sorry to say they don’t want women to know because they fear it would deter them from attending. It is wrong to keep back facts to get the punters in, however benign they may think their motives. Is that controversial?
It happens to be a sad and almost impossible to believe fact that the NHS is doing this. In 1997 Professor Baum resigned from the Screening Committee on the issue of telling the truth: he set up screening in 1989 and soon found unexpectedly high rates of DCIS which they didn’t know what to do with (and they are still wondering) - he wanted women told, which was only decent. Many would probably still have gone for screening, as the opinion on this thread indicates. However the Committee refused to tell women and gave this reason: if they told women about it they wouldn’t attend. They have gone on doing that ever since, although evidence that screening is not preventing deaths has mounted, and the latest leaflets, revised after pressure, are still squirmy on overdiagnosis - they neither name nor explain it and embed it in reassuring pink flowers well after the big (contested) claims that screening reduces the chance of death from bc.
Overtreatment is of the essence of screening, and should have been explained from the start: a screening test will always miss some, and catch some it shouldn’t have; the leaflet implies that these will be sorted out on recall by “further tests” - but it isn’t true, because they don’t know enough to know which are genuine cancers and which not, and if I had known that at least 850 women that year (that’s the most favourable estimate, that the NHS admits to - but not in the leaflets) would have had treatment they did not need I would not have gone. The NC estimate is 7000. Clearly a lot of women would still have gone - all I want is for women to be told so that people like me have our rights respected, you can have yours. And, surely, even if you decide it is still worth it, it should be your decision on fair evidence, and not manipulated by selective information? It is for the experts to judge whether as a programme it is cost effective.
I personally don’t have confidence in the independence of the review. It is such a political hot potato I can’t see them scrapping it. They certainly won’t throw away all those mammogram machines, and it would be hard to refuse mammograms to women asking for them after 20 years of near insistence that they have them. Just for good measure: Gordon Brown announced the age extension in 2007, but it does not appear to be evidence-based, there is good evidence that more screened women under 50 die of breast cancer than unscreened women, and it is suggested that is because intervention causes otherwise dormant cancers to spread. But it’s a votecatcher.
I’m really sorry to have gone on, but it’s not easy to get your head round but it is very serious.
s