State of Geographic Access to Cancer Treatment Trials in the United States: Are Studies Located Where Patients Live?

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In this study, we describe the geographic distribution of US cancer treatment trials to identify disparities and opportunities for targeted improvements in access to research for people with cancer. US-based phase I-III cancer treatment trials registered on ClinicalTrials.gov were tabulated for the years they were open to enrollment (2017-2022), overall and by county, and supplemented with data from the US Census Bureau, National Cancer Institute, Centers for Disease Control and Prevention, and US Department of Agriculture. We evaluated geographic differences in trial availability. We assessed 5-year trends in trials per capita and mapped 1-hour drive time areas around sites. A total of 6,710 trials were open to enrollment in 2022 across 1,836 sites. Trials increased by 4%, whereas sites decreased by 3% annually per capita from 2017. Seventy percent of US counties had no reported active trials in 2022 (2,211/3,143), representing 19% of people age ≥55 years. Eighty-six percent of nonmetropolitan counties had no trials versus 44% of metropolitan counties. Trial availability varied by county-level cancer mortality and social vulnerability (an index derived from demographic and socioeconomic data from the US Census). Eighteen percent of counties without trials had oncologist care sites (n = 618). Notably, 26% of people age ≥55 years lived beyond an hour drive of a site with ≥100 trials. Most US counties have limited to no trial offerings, a disparity magnified in counties that are nonmetropolitan, with high social vulnerability, and with high cancer mortality. Effort to facilitate diverse site participation is needed to promote equitable access to trials and to ensure patients participating in trials match the characteristics of patients who will receive interventions once approved. Counties with oncology care sites but no trials provide potential expansion areas.