Racial and Ethnic Differences in County-Level Availability of Uterine Cancer Clinical Trials

Importance Racial and ethnic disparities exist in clinical trial enrollment, but whether such disparities exist in geographic availability of uterine cancer trials is unknown. Objective To examine associations between race and ethnicity and county-level presence and rates of available uterine cancer clinical trials. Design, Setting, and Participants This retrospective cohort study linked Surveillance, Epidemiology, and End Results Research Plus; Aggregate Analysis of ClinicalTrials.gov; and American Community Survey data of adult patients (aged ≥18 years) diagnosed with uterine cancer between January 1, 2008, and December 31, 2021. The data analysis was performed between November 10, 2025, and September 9, 2026. Exposures Race and ethnicity categorized as American Indian or Alaska Native, Asian, Black, Hispanic (any race), Native Hawaiian or Pacific Islander, and White. Main Outcomes and Measures The main outcomes were county-level presence and rate of interventional uterine cancer trials. Hurdle models were used to estimate racial and ethnic differences in the odds of residing in a county with at least 1 trial and among patients in counties with trial availability, differences in rates of trials per person. Models accounted for county clustering and were adjusted for patient characteristics. Results Among 155 811 patients in the cohort (median [IQR] age at diagnosis, 62 [55-69] years; 1055 identifying as American Indian or Alaska Native [0.7%], 12 753 as Asian [8.2%], 16 303 as Black [10.5%], 23 177 as Hispanic [14.9%], 2175 as Native Hawaiian or Pacific Islander [1.4%], and 100 348 as White [64.4%] race and ethnicity), 121 525 (78.0%) resided in a county with at least 1 available trial. Trial availability was observed among 58.0% of American Indian or Alaska Native patients, 94.3% of Asian patients, 77.7% of Black patients, 86.1% of Hispanic patients, 90.3% of Native Hawaiian or Pacific Islander patients, and 74.1% of White patients. Compared with White patients, higher odds of residing in counties with at least 1 available trial were found for Asian (odds ratio [OR], 5.83; 95% CI, 4.83-7.12), Black (OR, 1.18; 95% CI, 1.07-1.30), Hispanic (OR, 2.18; 95% CI, 1.80-2.63), and Native Hawaiian or Pacific Islander (OR, 3.34; 95% CI, 2.17-5.66) patients, whereas American Indian or Alaska Native patients had lower odds (OR, 0.49; 95% CI, 0.39-0.61). Among patients in counties with at least 1 trial, fewer available trials per person were found for Asian (rate ratio [RR], 0.69; 95% CI, 0.65-0.74), Hispanic (RR, 0.56; 95% CI, 0.52-0.61), and Native Hawaiian or Pacific Islander (RR, 0.87; 95% CI, 0.80-0.95) patients compared with White patients. Conclusions and Relevance This cohort study of patients with uterine cancer found that racial and ethnic patterns in geographic trial availability differed by how availability was measured. The presence of any trial may not fully capture geographic access to clinical trial opportunities.