Vulnerability index impacts distribution of prostate cancer clinical trials in the United States

Abstract

Background Availability of clinical trials for prostate cancer in the US varies greatly by region. County-level analyses are vital to characterize healthcare access, disease burden, and population-level disparities. Methods Utilizing the ClinicalTrials.gov trial database, we collated all interventional prostate cancer trials between June 1, 2019, and June 1, 2025. We compiled data on county characteristics along with Social Vulnerability Index (SVI) designations derived from the CDC, NCI, and the Agency for Toxic Substances and Disease Registry data. A zero-inflated negative binomial regression model was used to evaluate trial availability. Trial characteristics were summarized using descriptive analysis. Results We found 884 eligible trials. Among 3,145 counties, only 631 had at least one clinical trial over the study period. Most trials (51%) included patients with metastatic disease. Sixteen percent of trials investigated curative treatments, while 65% examined palliative interventions. The majority of studies (52.5%) had funding from pharmaceutical companies. There was no significant relationship between trial availability and incidence or mortality rates. Among counties with at least one trial, those with a low SVI had twice as many trials per household when compared to those with high SVI (IRR 2.05, 95% CI 1.54 - 2.74, p<0.001). Counties with no trials were more rural (72.3% vs 22.0%) and had fewer specialist physicians (17.1% vs 69.1%). Conclusion Prostate cancer trials are disproportionately concentrated in the US, with lower representation in vulnerable areas. Expanding trial access to underserved areas is a crucial step in promoting equitable access to care.