The impact of mammography screening on breast cancer incidence

Evaluation of: Bleyer A, Welch HG. Effect of three decades of screening mammography on breast-cancer incidence. N. Engl. J. Med. 377, 1998-2005 (2012). Mammography screening must advance the time of diagnosis of breast cancer to be able to reduce the rate of death from breast cancer. This article examined the temporal effects of mammography on the stage-specific incidence of breast cancer in the USA from 1976 through to 2008. Despite substantial increases in the number of cases of early-stage breast cancer, only a marginal reduction was observed in the number of cases presenting with late-stage breast cancer. These results provide convincing evidence that mammography screening entails a substantial risk of detecting tumors that would not have become symptomatic during a woman's lifetime if no screening had taken place. To improve the effectiveness of screening mammography, more knowledge is needed on the natural history of breast cancer, especially the risk of progression from in situ to invasive breast cancer.