A Systematic Comparison of Overall Survival Between Men and Women With Triple Negative Breast Cancer

Introduction Triple-negative breast cancer (TNBC) in men is very rare. The clinical characteristics, prognostic factors, and overall survival of men with TNBC have not been characterized. Methods The study population consisted of men and women with a diagnosis of stage I-III TNBC between 2010 and 2016 in the National Cancer Database. Baseline demographic and tumor characteristics between men and women were compared using Pearson's Chi-Square test for categorical variables and Mann-Whitney U test for continuous variables. Kaplan–Meier and multivariate Cox proportional hazards regression model was used to compare survival and identify prognostic factors. Results A total of 311 men and 95,406 women with TNBC were included in the final analysis. The 3-year and 5-year overall survival was 74.8% and 68.8% in men, while it was 83.2% and 74.8% in women, respectively. In multivariate analysis, men were found to have a significantly worse overall survival compared to women (HR, 1.49, 95% CI, 1.19-1.86, P= .01). Older age at diagnosis, higher TNM stage, undergoing mastectomy and not undergoing chemotherapy or radiation were identified as independent negative prognostic factors in men with TNBC. Conclusion In one of the largest studies of men with TNBC, men were noted to have a poorer overall survival compared to women, despite adjusting for usual prognostic factors. Further research into differences in tumor biology, treatment patterns and compliance with therapy between men and women are needed to understand the underlying etiologies for the survival difference in TNBC.