Carcinoma of the male breast: update 1994.

In many ways, male and female breast cancers are similar, but do have some notable differences. Although the underlying etiology of male breast cancer may be partially due to hormonal or environmental changes, this disease is rare compared to female breast cancer. Most often, it presents as a painless lump, with estrogen receptor-positive infiltrating ductal carcinoma being the most common pathologic type. The main component of local therapy is either a radical or a modified radical mastectomy, with adjuvant chemotherapy proving useful. Estrogen receptor-positive tumors respond well to hormonal therapy. More research is needed in order to: (1) further characterize the molecular biological properties of male breast cancer tumors, (2) further investigate the role of adjuvant chemotherapy, and define successful regimens, and (3) determine optimal chemotherapy regimens in the treatment of metastatic disease. As this disease is a relatively rare condition, whenever possible, all patients should be allowed to participate in national cooperative group studies.