Sex differences in prognosis of primary bone cancer: a propensity score-matched study

Abstract Objectives Sex differences in survival in primary bone cancer have not been fully explored. Hence, this study was conducted to investigate the impact of sex on survival outcomes in patients with primary bone cancer. Methods The Surveillance, Epidemiology, and End Results (SEER)-17 database was used to identify patients with primary bone cancer. One-to-one propensity score matching (PSM) was employed to balance baseline characteristics. Kaplan-Meier curves and log-rank tests were used to evaluate differences in cancer-specific survival (CSS) and overall survival (OS) between sexes. Multivariate Cox regression analysis was performed to verify the independent effect of sex on survival, and sensitivity analysis was performed to determine the robustness of the results. Results A total of 8,791 patients were included, with 4,928 males (56.1 %) and 3,863 females (43.9 %), and a median follow-up time of 38 months. After PSM, 3,812 males and 3,812 females were included in the study, with balanced baseline characteristics between the groups. Post-PSM, females show significantly better CSS (HR=0.88, 95 % CI, 0.81–0.96, p=0.004) and OS (HR=0.87, 95 % CI, 0.81–0.94, p<0.001) compared to males. In multivariable Cox regression, the female sex was identified as an independent protective factor for both CSS (HR=0.86, 95 % CI, 0.79–0.94, p<0.001) and OS (HR=0.83, 95 % CI, 0.77–0.89, p<0.001). Conclusions Based on the analysis of SEER data with a large sample size, this study revealed that female patients with primary bone cancer have significantly better survival compared to males.