[Clinical research advancement on male breast cancer]

Male breast cancer is a rare disease and the incidence has increased over the past 25 years. Current knowledge regarding its biology, natural history, and treatment strategies is mainly based on the research findings on female breast cancer. Genetic risk factors include BRCA2 mutations. Occupational risk factors include high temperature environments and exhaust fumes. Hormonal imbalances, such as gonadal dysfunction, obesity, and radiation exposure also contribute to the occurrence of male breast cancer. It may be indolent or progress slowly, or invade rapidly. Most cases are ductal tumors and 10% of the cases are ductal carcinoma in situ. The surgical operation is usually mastectomy with axillary clearance or sentinel node biopsy. Indications for radiotherapy, as well as the steps and methods, are similar to that for female breast cancer. Because 90% of the patients are estrogen receptor-positive, tamoxifen is a standard adjuvant therapy, but some individuals could also benefit from chemotherapy. In this article, the latest information on the epidemiology, biology, and treatment of male breast cancer is reviewed.