Long-term survival outcomes of male breast cancer: the propensity score matching analysis of nationwide registry database

Background: s: Few studies have examined the prognosis of male breast cancer patients in Western countries. However, data on the long-term outcomes in Asian male patients are limited. Thus, we aimed to compare long-term survival outcomes between male and female patients including cancer-specific mortality. Methods: We included male patients diagnosed with primary breast cancer between 1981 and 2014 using nationwide data from the Korean Breast Cancer Registry (KBCR). After propensity score matching with female patients using covariates such as age, year of diagnosis, stage, and hormone receptor status, survival analyses using the Kaplan-Meier method and log-rank test were performed to evaluate breast cancer-specific survival (BCSS) and overall survival (OS). Results: After matching 680 patients, the median age was 62 years for male patients. Most patients underwent mastectomy, and 35.3 % had stage 1 disease. Ten years after diagnosis, there was no significant difference in the BCSS rates between the sexes. However, the OS rate was lower in males that in females (68.0 % vs. 79.0 %, p = 0.027). There was no significant improvement in survival outcomes among male patients in the late diagnostic period (2000–2010) compared to those in the early period (1981–1999). Conclusion: In this nationwide cohort study, we observed no improvement in survival outcomes among male breast cancer patients diagnosed in the recent years. Despite similar BCSS between sexes, male patients demonstrated significantly worse OS than female patients, likely due to higher non–cancer-related mortality.