Matched-Pair Long-Term Survival Analysis of Male and Female Patients with Breast Cancer: A Population-Based Study

Abstract Purpose: To examine the differences in long-term survival between male and matched female breast cancer cases based on data from the Shanghai Cancer Registry (SCR).Methods: Every male breast cancer case was matched with four female cases according to the year of diagnosis, age, tumor stage, and histological subtype. Cumulative observed overall survival (OS) and cancer-specific survival (CSS) rates were calculated using Kaplan-Meier survival estimates, and log-rank tests were applied to compare the survival rates of male and female cases. Cox proportional-hazards regression models were used to assess the hazard ratios (HR) and 95% confidence intervals (CI) for the association between sex and the risk of death.Results: 50,958 patients with breast cancer (0.85% male) were registered in the SCR between 2002 and 2013. After matching, 434 male and 1736 female patients were included in the study. With a median follow-up time of 10 years, men with breast cancer showed significantly worse OS (P < 0.0001) and CSS (P < 0.0001) than women. The 5- and 10-year OS rates for male and female patients were 67.27% and 77.75%, and 45.95% and 62.60%, respectively; the 5- and 10-year CSS rates for male and female patients were 70.19% and 79.79%, and 50.57% and 67.20%, respectively. Compared with women, men had 65% increased risk of overall death (95% CI: 1.42-1.92) and 70% increased risk of cancer-specific death (95% CI: 1.44-2.00).Conclusion: The study provided evidence at the population level that male patients with breast cancer had lower survival rates than women in China.