Assessing Geographic Disparities in the Availability of Renal Cell Carcinoma Clinical Trials in the United States

PURPOSE Clinical trials for cancer tend to be less available in regions of the United States corresponding to high socioeconomic vulnerability; however, specific patterns for renal cell carcinoma (RCC) have yet to be reported. The aim of this study was to evaluate the current county-level distribution of RCC trials in the United States and identify factors contributing to disparities of access. METHODS We performed a cross-sectional analysis of all interventional trials on ClinicalTrials.gov enrolling adult patients with RCC between June 1, 2019, and June 1, 2025. After mapping each US study site to its corresponding county, we used a zero-inflated negative binomial (ZINB) model to evaluate the relationship between county-level trial availability and corresponding Social Vulnerability Index (SVI) designations, renal cancer incidence rates, and renal cancer mortality rates. Trial characteristics were extracted and summarized descriptively. Incidence rate ratios were estimated to quantify the relationship between trial availability and county-level characteristics. RESULTS In total, 289 trials met the inclusion criteria, corresponding to a total of 5,028 unique trial sites. Only 672 (21.4%) of all US counties had at least 1 trial site; no state had a trial in every county. Compared with high-SVI counties, counties with low, low-medium, and medium-high SVIs had 3.1-fold, 2.0-fold, and 1.8-fold higher trial incidence rates (all P < .001). Higher renal cancer incidence and mortality rates were not significantly associated with county-level trial prevalence ( P = .55 and P = .40, respectively). CONCLUSION Most US counties lacked RCC clinical trial representation. Counties with higher social vulnerability had fewer trials, highlighting key structural disparities in access to new RCC interventions within the United States and emphasizing the importance of accounting for regional social vulnerability in the trial design and site selection process.