Characterizing travel burden in oncology clinical trials: A single-institution analysis.

Abstract

129 Background: Geographic access remains a significant barrier to enrollment of patients (pts) in oncology clinical trials. Previous studies have found that travel burden may disproportionately affect vulnerable racial and ethnic groups and contribute to inequities in trial enrollment (1). This study evaluated travel patterns among oncology clinical trial pts at an NCI-Designated Cancer Center and assessed disparities across race, ethnicity and primary language. Methods: We conducted a retrospective analysis of 8,319 consent events for California-residing oncology pts who signed consent to trials at the University of California, Los Angeles from 2013 to 2018. Home ZIP codes were geocoded to ZIP code centroids, and one-way driving distance (miles) and estimated travel time (minutes [min]) to the treatment site were calculated using the Google Maps Distance Matrix API under a standardized date and time to control for traffic variation. Primary outcomes included median travel distance and travel time stratified across race, ethnicity and primary language. Secondary outcomes included the proportion of patients with travel times exceeding 30 and 60 min. For continuous outcomes, all pairwise group comparisons were performed using Wilcoxon rank-sum tests. For binary outcomes, all pairwise group combinations were performed using two-proportion z-tests. All p-values were adjusted for multiple comparisons using the Benjamini-Hochberg false discovery rate method, and statistical significance was defined as an adjusted p-value < 0.05. Analyses were performed using R statistical software. Results: Median one-way travel time was 55 min and median distance was 25.4 miles; 77% of the cohort traveled >30 min and 42% of the cohort traveled >60 min. Overall, Black pts had shorter median one-way travel time and distance (42 min; 16.2 miles) compared to White pts (56.5 min; 26.7 miles; p<0.001) and were less likely to travel >60 min (23.0% vs. 44.7%). When comparing non-Hispanic White (NHW) pts to other pts, NHW pts traveled farther (28.3 vs. 23.1 miles; p<0.001). Spanish speaking pts traveled shorter distances than English speakers (21.2 vs. 25.7 miles; p<0.001). Conclusions: Within our single-center analysis, Spanish-speaking and Black pts traveled shorter distances to trial enrollment while Non-Hispanic White pts traveled farther compared to other pts. These patterns may reflect geographic self-selection and the presence of socioeconomic barriers that limit how far minority pts are able to travel. Overall, minority groups are underrepresented among long-distance enrollees, suggesting that those facing the greatest travel burden may never reach enrollment in the first place. These findings underscore the need for targeted interventions aimed at improving clinical trial accessibility for underserved populations. 1. https://academic.oup.com/oncolo/article/23/10/1242/6439749.