[Epidemiology of breast cancer in men].

Incidence data for male breast cancer from 34 selected cancer registries in different parts of the world are presented. The geographic variation in incidence is similar to that observed for female breast cancer, resulting in a strong correlation between their respective rates, although certain populations have higher rates for male breast cancer than expected from the female incidence, notably Israeli Jews and blacks in the United States. It seems that both environmental factors (acting by the intermediary of endogenous oestrogens excess) and genetic predisposition play a role in determining the epidemiological profile of male breast cancer, as they do for cancer of the female breast.