Clinicopathologic Features and Radiation Therapy Utilization in Patients with Male Breast Cancer: A National Cancer Database Study

Male breast cancer (MBC) accounts for approximately 1% of all breast cancers, limiting the data characterizing clinicopathologic features and treatment outcomes in patients with MBC. This paucity of data has led to most of our treatment guidance being extrapolated from patients with female breast cancer (FBC). From 1998 to 2012, data were captured using the National Cancer Database to identify patients with nonmetastatic MBC (n = 23 305) and FBC (n = 2 678 061). Tumor and clinicopathologic features were obtained and compared. Patients with MBC were more likely to have invasive disease, T2-4 tumors, centrally located tumors, positive lymph nodes, estrogen receptor–positive or progesterone receptor–positive tumors, lymphovascular space invasion, and were less likely to have Her2/neu-positive or triple-negative tumors. All of these differences were statistically significant (P < .001). Treatment comparisons showed that patients with MBC were more likely to undergo mastectomy and less likely to undergo breast...