Statistical Analysis
Chi-square tests were used to assess differences in the independent variables of interest across the four racial groups. Kaplan-Meier curves were used to estimate the unadjusted overall survival by race. The log rank test was used to estimate the differences in survival among the racial groups. Multivariable Cox proportional hazards models were used to determine the differences in overall risk of mortality in the study sample based on the independent variables including race, age at diagnosis, Yost Quintile, stage, tumor grade, histology, radiation, chemotherapy, and surgery.. All Chi-square tests and survival analyses were conducted using SAS version 9.4 statistical software, with p-values <0.05 considered significant.