Young adult males have worse survival than females that is largely independent of treatment received for many types of central nervous system tumors: A National Cancer Database analysis

Background Central nervous system (CNS) tumors rank among the top 5 cancers diagnosed in young adults aged 20 to 39 years at diagnosis and show a clear male excess in incidence. It is unknown whether sex differences in survival persist across histologic types and depend on the treatment received. Methods From the National Cancer Database (2004-2016), young adults (aged 20-39 years) who had been diagnosed with CNS tumors were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated as measures of association between sex and death via Cox regression. An inverse odds weighting mediation analysis was performed with treatment received as a mediator. Results There were 47,560 cases (47% male). Males had worse overall survival than females for 9 of 16 histologic types, including diffuse astrocytoma, glioblastoma, and meningioma (all P < .05). Males had an increased risk of death after a brain tumor diagnosis overall (HR, 1.47; 95% CI, 1.41-1.53) and for 8 histologies. There was a significant association between male sex and death overall that was mediated by treatment received (indirect-effect HR, 1.17; 95% CI, 1.15-1.18), but no single histology had a significant indirect effect. All histologies examined in mediation analyses had significant direct effects for sex. The excess mortality due to sex was 20% for all CNS tumors combined and 34% among males with CNS tumors. Conclusions Overall, treatment received may mediate a portion of the association between sex and death after a CNS tumor, but sex itself appears to be a stronger risk factor for death in this study.