Radiation risk and mammographic screening of women from 40 to 49 years of age: effect on breast cancer rates and years of life

The aim of this study was to evaluate the carcinogenic risks associated wit h radiation in mass mammographic screening. Assessment was in terms of brea st cancer mortality and years of life for a hypothetical cohort of 100 000 women. Data were obtained on incidence, mortality and life expectancy for t he female population of Stockholm. With a screening interval of 18 months a t ages 40-49 years, a total absorbed dose to the breast of 13 mGy per invit ed woman; and an annual breast cancer reduction of 25% per year 7 years fro m screening start, the net number of years gained was at least 2800. Howeve r, using the highest absorbed dose reported in routine mammographic screeni ng in Sweden (approximate to 3 mGy per view), and the highest reported radi ation risk in the literature, a programme entailing annual screening with 2 views would require at least a 20% annual reduction in breast cancer morta lity to give a net benefit in both the number of years of life gained and n umber of breast cancer deaths avoided. This observation supports the conclu sion that exposures with low absorbed dose are essential when performing ma ss screening with mammography among young women. (C) 2000 Cancer Research c ampaign.