Male breast cancer
Male breast cancer (MBC) is an uncommon condition, accounting for 0.5-1% of all breast cancers. Although MBC has its specific characteristics, the lack of large randomized trials of this disease resulted in the need of extrapolating data from female breast cancer to offer these patients an adequate medical management. Mean age at diagnosis of MBC is 67 years, men being diagnosed at an older age than women with this disease. Patients with MBC have lower survival rates (5-year-survival – 67%) than postmenopausal women and relatively similar outcomes to premenopausal female patientswith breast cancer. There are certain genetic conditions that determine a higher lifetime risk of developing MBC. The risk of MBC is up to 50 times higher in individuals with Klinefelter’s syndrome compared to individuals with normal karyotype. This chromosomal disorder is found in 7.5% of men with breast cancer. The lifetime risk of breast cancer is even higher (up to 100 times) in men with BRCA2 mutations. Hyperestrogenism (due to hepatic insufficiency, testicular failure), hyperprolactinemia, alcohol intake and tobacco smoking, occupational risks (especially working in hot environments), slightly increase the risk of developing MBC. Gynecomastia, a very common disorder in young men, has no influence on the risk of MBC. The majority of malignant breast tumors in men are epithelial (carcinomas) with a ductal invasive (NST) histologic type. As the male mammary gland lacks lobular tissue, invasive lobular carcinoma of male breast is extremely rare. Most MBC are luminal A and B molecular subtypes. HER2neu is usually negative in MBC (in 95% of cases).