October is with us again. Unfortunately, it has been painted pink. This month cancer charities and others gear up to urge women to attend breast screening as the best means of avoiding death from this disease. Sadly, these well-meaning messages are inaccurate and patently false because they are based on out-dated information.
Medical understanding of breast cancers has moved on from believing ‘find it small and it will save your life’. It just does not work like that: small cancers found by screening may never grow larger or be a problem in a lifetime, whereas larger cancers may grow rapidly and take lives – or vice versa – the problem is no-one can identify which will be killers. So breast screening of healthy women (ie without breast symptoms) finds thousands of ‘changes’, some of which will be harmless, but will nevertheless go on to be treated. This is ‘overdiagnosis’ (different from the ‘false positive’ results, when women are mistakenly told they have cancer) – see earlier links to many research papers.
Contrary to what was thought in the past, “finding it ‘early’ (ie ‘small’ – how can anyone know how early…? ) will save your life” turns out not to be the case. So why do breast screening programmes continue when there is now an accumulation of robust research which shows screening (as opposed to diagnostic imaging when someone has symptoms) actually causes more harm than benefit, if any?
Breast-Cancer Tumor Size, Overdiagnosis, and Mammography Screening Effectiveness
H. Gilbert Welch, M.D., M.P.H., Philip C. Prorok, Ph.D., A. James O’Malley, Ph.D., and Barnett S. Kramer, M.D., M.P.H.
N Engl J Med 2016; 375:1438-1447October 13, 2016