[Breast cancer: epidemiology, risk factors, screening].

Breast cancer is the most frequent cancer in women: more than 8 to 9% of women will develop a breast cancer during their life and the incidence rate is regularly increasing. Despite therapeutic improvements, breast cancer mortality still remains important and varying according to regions (five years survival: 62 to 80% for the last years). The risks factors analysis shows that a primary prevention of the major risks factors is not yet possible (genetic or endogenous hormonal risk). The chemoprevention is still is discussion and under investigation. For the moment, secondary prevention using screening is the only way to improve survival. The lead-time induced by the screening allows an earlier detection of breast cancers. The randomized trials have demonstrated a significant benefit on mortality and morbidity from breast cancer in women aged 50 to 69. So many countries started regional, pilot or national breast cancer screening programmes using mammography with a 2-year interval and specialized centers.