Survival differences by racial and ethnic group have been reported in children and adolescents with germ cell tumors (GCTs), but whether these differences depend on stage of disease is unclear. Using the SEER 18 registries (2000-2015), we examined GCT survival differences by race/ethnicity (non-Hispanic white [NHW], Black, Asian/Pacific Islander [API], Hispanic) separately for males and females aged 0-19 years at diagnosis. We used Kaplan-Meier survival curves (Log-Rank p values) to characterize survival differences. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between race/ethnicity and death. Using an inverse odds weighting mediation analysis, we estimated the association between race/ethnicity and death treating stage of disease as the mediator. There were no significant racial/ethnic survival differences among females. Male survival differed by race/ethnicity (p < 0.0001) with NHW males having the best survival. Compared to NHW, API and Hispanic males had significantly higher risks of death (API HR: 2.18; 95% CI: 1.32-3.56; Hispanic HR: 1.98; 95% CI: 1.42-2.78) (model adjusted for age and year at diagnosis, tumor histology and location, stage). This association was mediated by stage of disease only among Hispanic males with gonadal tumors (indirect HR: 1.18; 95% CI: 1.03-1.35). The increased risk of death after a testicular GCT diagnosis observed among Hispanic males was mediated by stage of disease. For API males and Hispanic males with extragonadal tumors, other unidentified factors including differences in exposures, tumor biology or treatment received may impact the observed racial/ethnic survival disparities.
International journal of cancer. 2019 Jul 15 [Epub ahead of print]
Lindsay A Williams, A Lindsay Frazier, Jenny N Poynter
Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN., Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, MA.