ED-34 * IDENTIFICATION OF FACTORS IN GLIOBLASTOMA NOT RECEIVING UPFRONT RADIATION THERAPY

Abstract

BACKGROUND: Radiation therapy (RT) is the standard of care for GBM. Analysis of the Surveillance, Epidemiology, and End Results (SEER) database by several investigators including our group have demonstrated 27% of GBM cases did not receive upfront radiation therapy and had a poorer survival outcome. Our study sought to investigate the sociodemographic factors in this group. METHODS: We analyzed the SEER 18 dataset for GBM patients that are 20 years and older from 2000-2010 (n = 23,595). All statistical tests were two-sided, and significance defined as p < 0.05. To examine different variables, hazard ratios (HR) and the corresponding 95% confidence limits (CL) are to be estimated using Cox regression models including multivariable models for all estimates adjusted for all covariates. Data are analyzed using SEER-Stat. RESULTS: We found age to be a highly significant factor, the older more likely to not receive upfront RT, however the 20-49 age group had 696 of 4025 cases (17.29%) not receive treatment. Adjusted for age women were less likely to receive RT. Having had a gross total resection increased the likelihood of receiving RT vs. partial resection or biopsy. Patients having their tumor in the parenchyma of the neocortex were more likely to receive RT versus in the ventricles or cerebellum. There was a slight increase in use of RT over our study-period and there was also a statistically significant increase of not receiving RT if black, living in a lower education and greater poverty area or rural environment. CONCLUSION: The sociodemographic factors we identified with not receiving upfront RT are known to be associated with health disparities; however, there were many cases in the favorable categories that did not receive RT. Our results demonstrate that improving the use of upfront RT should have a marked improvement in GBM outcomes.