Comparing the Characteristics and Outcomes of Male and Female Breast Cancer Patients in Korea: Korea Central Cancer Registry

PURPOSE: This study aimed to determine the incidence of male breast cancer (MBC) and its survival outcomes in Korea, and to compare these results to those for female breast cancer (FBC). MATERIALS AND METHODS: We searched the Korea Central Cancer Registry and identified 227,122 breast cancer cases that were diagnosed between 1999 and 2016. Demographic and clinical characteristics and overall survival (OS) rates were estimated according to sex, age, histological type, and cancer stage. RESULTS: The 227,122 patients included 1,094 MBC cases and 226,028 FBC cases. Based on the age-standardized rate, the male: female ratio was 0.0055:1. The most common ages at diagnosis were 60-69 years for MBC and 40-49 years for FBC (p < 0.001). Male patients were less likely than female patients to receive adjuvant radiotherapy (7.5% vs. 21.8%, p < 0.001) or adjuvant chemotherapy (40.1% vs. 55.4%, p < 0.001). The 5-year OS rates after diagnosis were 88.8% for all patients, although it was significantly lower for MBC than for FBC (76.2% vs. 88.9%, p < 0.001). In both groups, older age (≥ 60 years) was associated with shorter survival. The 5-year OS rates for the invasive histological types were 75.8% for men and 89.0% for women. The 5-year OS rates in both groups decreased with increasing cancer stage. CONCLUSION: MBC was diagnosed at older ages than FBC, and male patients were less likely to receive radiotherapy and chemotherapy. The survival outcomes were worse for MBC than for FBC, with even poorer outcomes related to older age, the inflammatory histological types, and advanced stage. It is important that clinicians recognize the differences between FBC and MBC when treating these patients.