Do women under the age of 50 benefit from mammogram screening?
Latest findings from the Swedish study - involving nearly 250,000 women - suggests not, but mammography could be worthwhile for those aged 60-69.
These are the women for whom screening seems to have the greatest benefits, with 33 per cent fewer deaths in the screened group due to breast cancer compared with those not screened.
The differences start to become significant after the age of 55, but there is hardly any variation between the screened and unscreened groups before then.
In all, the study followed 129,750 women who were screened and compared them with a control group of 117,260 women who were not. Overall, the screened group had 21 per cent fewer breast cancer deaths than the unscreened one.
Groups dedicated to cancer prevention have criticised earlier reports from the Swedish researchers for being 'unscientific', although such a response may only be to legitimise the sense of disappointment that the study's authors have never been prepared to make outright positive statements on breast screening for all age groups.
In this latest study, the researchers - from the University Hospital in Stockholm - say there are no grounds for criticising their findings for scientific reasons (Lancet, 2002; 359: 909-19).