The Panel determined: of 75 women given a diagnosis by screening, 16 will die of cancer anyway, 37 are treated and survive – as they would have done if diagnosed due symptoms, 17 are over-diagnosed, only 5 women’s lives are ‘saved’ from breast cancer by screening.
So – On this basis (and dividing by 5) for every one woman given a screen-diagnosis who has her life saved from breast cancer, there are 3 over-diagnoses (extra cancer ‘victims’) and 11 women for whom the screen diagnosis makes no material difference. The figures might not even be this good as the panel didn’t perform a systematic review, or use ‘all cause mortality’ (which would include deaths from heart problems etc due to radiotherapy).
So for every 15 women who are ‘screen-diagnosed
- 1 will not die of breast cancer (so screening ‘worked’) (5/75)
- 3 will have been given over-diagnosis of a ‘cancer’ that would never have bothered them in their lifetime (so screening didn’t work and was damaging) (17/75)
- 8 would have still lived (so screening, although bringing diagnosis forward, didn’t work but didn’t harm – although being made a cancer patient earlier/for longer is harmful if early diagnosis was not necessary) (37/75)
- 3 will still die of breast cancer (so screening didn’t work) (16/75)
And these figures are over-optimistic re the benefits of screening! See statement on Cochrane website http://www.cochrane.dk/screening/comments-on-UK-panel.htm