Racial disparities in geographic access to uterine cancer clinical trials across U.S. counties

Purpose: Uterine cancer mortality is rising, disproportionately affecting racially and socioeconomically marginalized populations. Clinical trials improve access to novel therapies and outcomes, yet racial disparities in trial enrollment persist. Because the geographic distribution of trials shapes opportunities for enrollment, we examined associations between race and county-level availability of interventional uterine cancer trials, and whether this relationship varies by neighborhood vulnerability. Methods: We identified US-based uterine cancer interventional trials from the Aggregate Analysis of ClinicalTrials.gov database (2008-2021) and aggregated site ZIP codes to counties, counting multiple sites per county as one trial. County-level trial availability was linked to the CDC Social Vulnerability Index (SVI; range 0-1, higher scores = greater vulnerability) and uterine cancer cases in SEER (2008-2021). Multivariable logistic regression estimated associations between race/ethnicity (American Indian/Alaska Native, Asian, Black, Hispanic, Native Hawaiian/Pacific Islander, and White) and county-level trial availability, adjusting for clinical characteristics and county size. Effect modification by SVI [high (≥90th percentile) vs. low (<90th percentile) was assessed. Results : We included 151,610 uterine cancer cases (mean [SD] age at diagnosis, 61.7 [11.7] years) diagnosed between 2008 and 2021. Two-hundred and twenty-five unique interventional uterine cancer clinical trials were open in the year of diagnosis and county of residence for these cases; 78% lived in a county with at least one open interventional trial. Compared to White women, Asian, Black, and Native Hawaiian/Pacific Islander women had higher odds of trial availability, whereas American Indian/Alaska Native and Hispanic women had lower odds. We observed effect modification by SVI (p-interaction <0.001): in areas of high vulnerability, Black compared to White women had higher odds of trial availability (OR=1.31, 95% CI=1.08-1.60). Conclusions : Our findings highlight racial disparities in geographic access to uterine cancer clinical trials - an essential prerequisite for enrollment. Among residents of more socially vulnerable areas, trial availability was higher for Black than White women, contrasting with prior research showing lower enrollment among Black patients. This suggests structural barriers beyond proximity continue to limit equitable participation, even where trials are accessible.