[Cancer of the breast. I. Epidemiology and risk factors (our experience)].

Data concerning different risk factors for breast cancer based upon the results obtained in a study of 461 women are reported. Comparing this experience with other Italian and international series, it is concluded that the most reliable risk-index for breast cancer is the age of the woman, while less incisive, though prominent, are family history, immunodeficiency, hormonal metabolism and other environmental factors.