Racial and Ethnic Disparities in Molecularly-Defined Primary Brain Tumors: Analysis of 53,675 Cases from the Central Brain Tumor Registry of the United States (2018-2021)

Introduction: Molecular profiling has revolutionized brain tumor (BT) diagnosis and treatment. Most frequently descriptions of these subtypes have been performed within institutional series, and the extent to which incidence of molecularly-defined BT (MDBT) varies by demographics is unknown. Collection of brain tumor molecular markers by US cancer registries began in 2018. We examine national-level incidence patterns of MDBT to investigate variation by race/ethnicity.

Methods: Average annual age-adjusted incidence rates (AAAIR) per 100,000 (standardized to the 2000 US standard population) from 2018-2021 for MDBT types were generated from the Central Brain Tumor Registry of the United States, a combined dataset of the CDC’s National Program of Cancer Registries and the NCI’s Surveillance, Epidemiology, and End Results Program. Multinomial logistic regression was used to examine associations between race/ethnicity, age, sex, and urbanicity and MDBT incidence.

Results: Among 53,675 MDBTs, IDH-wildtype glioblastoma (IDHwt-GBM) was most common (N=39,404). Non-Hispanic White (NHW) individuals had significantly higher incidence of all MDBT gliomas compared to other racial/ethnicities (p < 0.001). Increased age was associated with higher incidence of MDBT for all glioma subtypes versus IDH-mutant astrocytoma (IDHmut-Astro) (OR:1.02-1.10, p< 0.001). Among males, the odds of IDHwt-GBM versus IDHmut-Astro were higher than females (OR:1.19). Urbanicity was not a significant predictor of MDBT risk. For non-Hispanic Black individuals, the odds of IDHwt-Astro or IDHwt-GBM (versus IDH-mut Astro) were 1.33 and 1.36 times higher than NHW persons, respectively, but the odds of IDH-mutant and 1p/19q co-deleted oligodendroglioma (IDHmut-codel) versus IDHmut-Astro were lower than NHW individuals (OR:0.79, p< 0.05). Among Hispanic individuals of all races, odds of IDHmut-codel versus IDHmut-Astro were higher than NHW individuals (OR:1.19, p< 0.05).

Conclusion : Our findings reveal significant disparities by race/ethnicity with notable variations in the incidence and odds of MDBT gliomas based on IDH-mutation status, underscoring the complexity and value of molecular subtyping for improved risk assessment and continued research.