Most breast cancers in men are ductal carcinomas. Ductal means the cancer started in the milk pipes of the breast, called ducts. These cancers are usually invasive because they start inside the duct and then break through the wall of the duct, growing into the normal surrounding breast tissue.
The 17-yr incidence of male breast cancer was analyzed from data of the Israel Cancer Registry for Jews and non-Jews, and for the Jewish subgroups of European/American-born and Asian/African-born. The 187 observed cases among Jewish males in Israel were compared with the 194 cases reported in the U.S.