P14.21.b Impacts of Sex and Race/Ethnicity on Incidence of Vestibular Schwannoma Across the Lifespan in the United States

BACKGROUND Vestibular schwannomas (VS) are benign tumors arising in the vestibulocochlear nerve. Previous research has identified sex and racial/ethnic differences in risk for these tumors with higher incidence occurring in female and older White populations, and poorer overall survival among Hispanic and Black populations. In this analysis, we aim to assess the joint effects of age, sex, and race and ethnicity on incidence of VS. MATERIAL AND METHODS The Central Brain Tumor Registry of the United States (CBTRUS) is an aggregation of data from the CDC’s National Program of Cancer Registries and NCI’s Surveillance, Epidemiology and End Results Program which, in combination, cover the entire US population. VS was defined using ICD-O-3 histology (9560/1) and topography (C72.4) codes for individuals diagnosed between 2004 and 2021, and excluded cases diagnosed by autopsy or death certificate only. We calculated average annual age-adjusted incidence rates, and incidence rate ratios (IRRs) by sex, race/ethnicity, and age at diagnosis. IRRs were considered statistically significant at a P-value<0.05. Statistical interaction was determined using Poisson models. RESULTS A total of 76,852 VS cases were diagnosed from 2004-2021 (53.0% female). Overall, 81.2% of cases were in non-Hispanic White persons, while 8.2% were in Hispanic persons (any race) and 4.9% were in non-Hispanic Black persons. Incidence of VS peaked in those 60-69 years. Incidence was significantly higher among females from 10-59 years, with peak female/male difference in ages 20-29 years (IRR=1.29, p-value<0.001). Non-Hispanic Black persons had significantly lower incidence compared to non-Hispanic White persons overall, within sexes, and when stratified by sex or age group. The magnitude of the observed difference by sex varied with race/ethnicity. There was a significant statistical interaction between racial ethnic group and sex (race/ethnicity*sex) for those 50-59 years and 70-79 years. This observation held when restricted to those diagnosed with radiographic confirmation only, but no significant interaction by race/ethnicity and sex occurred among those diagnosed with microscopic confirmation, suggesting it may result from varying diagnostic patterns or access to care. CONCLUSION This study identifies an elevated risk of VS in Non-Hispanic Whites individuals relative to both Non-Hispanic Black and Hispanic individuals, beginning shortly after puberty and continuing to middle adulthood. Non-Hispanic Black race/ethnicity conferred decreased risk of VS more significantly among men than among women. These results identify significant differences in the incidence of VS by race/ethnicity, sex, and age.