Male breast cancer and female breast cancer: A population-based study

Abstract Male breast cancer (MBC) is a rare disease. Due to limited information, MBC has always been understudied. We conducted a retrospective population-based cohort study by using the 2010–2014 Surveillance, Epidemiology, and End Results (SEER) program data. The clinical and biological features of female breast cancer (FBC) patients were compared with MBC patients. Survival curves were constructed with the Kaplan-Meier method. Multivariate Cox regression models and competitive risk models were separately built to identify factors associated with survival time in the MBC and FBC group. Our retrospective study showed that MBC patients suffered with higher TNM stages, higher grades, and more percent of hormone receptor–positive tumors, compared with FBC patients. In addition, the site of the primary breast cancer varied greatly different between genders. FBC patients demonstrated superior overall survival than MBC patients on Kaplan-Meier analysis. In multivariate COX analysis for FBC patients, older age, black race, higher T, N, M-stages, higher grades, estrogen receptor (ER)/progesterone receptor (PR) negative and human epidermal growth factor receptor 2 (HER2) negative were associated with higher risk of death. MBC patients had similar independent prognostic factors, but PR and HER-2 status did not appear to independently influence survival. Interestingly, primary site location was an independent prognostic factor for both MBC patients and FBC patients, which should be considered by clinicians as a prognostic factor.