Geographic distribution and equity in access to gastrointestinal cancer clinical trials in the United States.

807 Background: Geographic access to clinical trials is critical for equitable cancer care. Gastrointestinal (GI) cancers—including colorectal, pancreatic, liver, gastric, esophageal, and biliary—account for over a quarter of U.S. cancer deaths. Despite this burden, the geographic distribution of active GI cancer trials has not been systematically evaluated, particularly by cancer subtype and population factors such as rurality, socioeconomic status, and race/ethnicity. Methods: All active, interventional Phase I–III GI cancer trials were identified from ClinicalTrials.gov (accessed September 5, 2025), restricted to U.S.-based therapeutic studies. Trial sites were geocoded by ZIP code and mapped to 2020 Census ZIP Code Tabulation Areas (ZCTAs). Geographic access was defined as the proportion of the U.S. population residing within 30 or 60 miles of a site using Haversine distance. Analyses were stratified by cancer subtype, rurality (RUCA codes), income quartile, and race/ethnicity (ACS 2023). Results: We identified 958 active GI cancer trials (287 colorectal, 260 pancreatic, 136 gastric, 86 esophageal, 108 hepatocellular carcinoma [HCC], 81 cholangiocarcinoma) across >4,400 U.S. ZIPs. At 30 miles, population coverage exceeded 80% for colorectal and pancreatic cancers but was lower for HCC (61%) and cholangiocarcinoma (64%). At 60 miles, coverage was >90% for colorectal, pancreatic, and gastric cancers but remained