Survival in male breast cancer (MaBC) over the past three decades.

Abstract

569 Background: Breast cancer mortality in women has declined significantly over the past several years. In men, it is unclear whether survival has changed over time. The aim of this study was to evaluate changes in breast cancer-specific survival (BCSS) and overall survival (OS) in MaBC over the past three decades. Methods: We evaluated men diagnosed with breast cancer between 1988 and 2017, with known cause of death reported in the Surveillance, Epidemiology, and End Results registry. Patients were categorized into 3 groups by year of diagnosis: 1988-1997, 1998-2007 and 2008-2017. BCSS and OS were estimated by Kaplan-Meier and differences between groups were compared by log-rank test. Cox proportional hazards regression was used to evaluate the independent association of tumor and patient characteristics with BCSS and OS. Results: We included 8,412 men diagnosed between 1988-1997 (N = 1,033), 1998-2007 (N = 2,938) and 2008-2017 (N = 4,441). Median age for the overall population and within each decade of diagnosis was 68 years. Median follow-up was 23.6 years, 14.3 years and 4.5 years in periods 1988-1997, 1998-2007 and 2008-2017, respectively. Overall, BCSS at 5 years was 83.5%, 83.6% and 84.3% in periods 1988-1997, 1998-2007 and 2008-2017, respectively; p = 0.8. There was no significant difference in BCSS between the three periods of diagnosis within each stage of breast cancer (stage I, II, III and IV). Among all patients, OS at 5 years was 64.7%, 67.2% and 69.3% in periods 1988-1997, 1998-2007 and 2008-2017, respectively; p = 0.01. In multivariate Cox models, older age at diagnosis, black race, grade 3 disease, increasing stage, hormone receptor negative status and no surgery were all independently associated with worse BCSS and OS. In these adjusted Cox models, each additional year of diagnosis had no significant association with BCSS (hazard ratio, 1.0; 95% CI, 0.99 – 1.01; p = 0.78), and a significant improvement in OS (hazard ratio, 0.99; 95% CI, 0.98 – 0.99; p = 0.01). Conclusions: Over the past three decades, there has been no significant improvement in BCSS in MaBC. The changes in OS over time suggest increasing life expectancy. Efforts to improve BCSS in MaBC are warranted.