Clinical Pearls & Morning Reports
Published June 13, 2018
The lifetime risk of breast cancer for a man is approximately 1:1000, as compared with 1:8 for a woman. Read the latest NEJM Review Article here.
Q: What are some of the risk factors for breast cancer in men?
A: As is the case with many cancers, breast cancer in men is an age-related disease, with incidence rates rising steadily with age. The risk of breast cancer is doubled for men who have a first-degree relative with the disease. Mutations in BRCA are among the most clearly established risk factors for breast cancer in men. Radiation exposure has been reported as a risk factor for breast cancer in men. Conditions that are associated with elevated estrogen levels are also linked to breast cancer in men, including gynecomastia, liver disease, testicular abnormalities, and obesity. Klinefelter’s syndrome has been associated with an increased risk of breast cancer in men.
Q: Are the pathologic characteristics of breast cancers in men similar to those of breast cancers in women?
A: Most cases of breast cancer in men are invasive carcinomas, with invasive ductal carcinoma by far the most prevalent histologic type. Less common histologic subtypes in men include papillary cancers (in 2 to 3% of cases) and mucinous cancers (in 1 to 2% of cases). Although lobular carcinomas account for approximately 12% of invasive cancers in women, this subtype is much less prevalent among men, accounting for only 1 to 2% of cases. Overall, breast cancers in men are more likely to be positive for estrogen receptor and negative for human epidermal growth factor receptor 2 (HER2) than breast cancers in women, although the incidence of these markers is similar to that in older, postmenopausal women.
A: Population-based studies have shown that 0 to 4% of men with breast cancer have BRCA1 mutations, and 4 to 16% have BRCA2 mutations. The risk of breast cancer is substantially lower among healthy men with BRCA mutations than among healthy women with BRCA mutations. The National Comprehensive Cancer Network (NCCN) guidelines recommend that men with BRCA mutations receive breast self-examination training and education and undergo yearly clinical breast examination, starting at the age of 35 years, with prostate cancer screening considered (for BRCA1 mutation carriers) or recommended (for BRCA2 mutation carriers) starting at the age of 45 years. The guidelines note that data in support of breast imaging in men are limited, and the guidelines do not include recommendations to screen male BRCA mutation carriers with mammography or magnetic resonance imaging.
A: Since no randomized trials of local therapy have focused on men with breast cancer, treatment approaches are extrapolated from studies of treatment for women with breast cancer. Women with newly diagnosed breast cancer often undergo breast-conserving therapy (i.e., lumpectomy and whole-breast irradiation), but most men undergo mastectomy with either axillary lymph-node dissection or sentinel-node biopsy. Even in men with early-stage disease, breast conservation is not common, despite the absence of any medical contraindication. An analysis of data from the Surveillance, Epidemiology, and End Results (SEER) registries showed that only 18% of men with T1N0 tumors, according to the tumor–node–metastasis (TNM) staging system, underwent breast-conserving surgery. Although not commonly used, breast-conserving therapy has been associated with survival rates equivalent to those associated with mastectomy in observational studies, suggesting that data from trials of surgery in women may be safely applied to men.