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

Abstract

Purpose: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

FIG 1.

Process for selecting active oncology trials. Data source: ClinicalTrials.gov. ^aIncludes ClinicalTrials.gov synonyms: cancer; neoplasms, tumors, tumor, neoplasm, malignancies, cancers, oncology, malignancy, tumors, tumor, neoplasia, malignant neoplasm, malignant tumors, malignant tumor, malignant neoplasms, primary cancer, neoplastic disease, cancer NOS, neoplasias, neoplastic syndrome, primary malignant neoplasm, tumor NOS, malignant neoplastic disease, malignant tumors, malignant tumor, malignant neoplasm primary. FDA, US Food and Drug Administration; NOS, not otherwise specified.

FIG 2.

Counties by presence of cancer trials versus oncologist care sites (2022). Data sources: ClinicalTrials.gov and data.Medicare.gov.^, Presence of trials means at least one cancer phase I-III trial open in 2022; presence of oncologist care site means at least one hematologist, medical oncologist, hematologist/oncologist, gynecologic oncologist, surgical oncologist, or radiation oncologist with a practice location and billing Medicare in 2022.

FIG 3.

(A) County characteristics by number of trials. Data sources: ClinicalTrials.gov, Rural Urban Continuum Codes, Social Vulnerability Index, and State Cancer Profiles.^,- (B) County characteristics by number of proximal trials (incorporating county adjacency). Data sources: ClinicalTrials.gov, Rural Urban Continuum Codes, Social Vulnerability Index, and State Cancer Profiles.^,- Q1-Q3 = first-third quartiles, Q4, fourth quartile. ^aNonmetropolitan, Q4 Social Vulnerability Index, Q4 Cancer Incidence, and Q4 Cancer Mortality counties defined as high vulnerability counties. ^bP < 0.01 in chi-square analysis.

FIG 4.

(A) Areas within an hour drive of a limited or broad portfolio trial site.^a Data sources: ClinicalTrials.gov and the US Census Bureau's American Community Survey.^{, a}Limited portfolio site defined as having 1-99 active oncology trials in 2022 (n = 1,523 sites). Broad portfolio site defined as having ≥100 active oncology trials in 2022 (n = 313 sites). (B) Areas within an hour drive of a broad portfolio trial site^b versus people age ≥55 years by census tract. Data sources: ClinicalTrials.gov and the US Census Bureau's American Community Survey.^{, b}Broad portfolio site defined as having ≥100 active oncology trials in 2022 (n = 313 sites). (C) Percentage of people age ≥55 years who live within an hour drive of a broad portfolio trial site^c by state. Data sources: ClinicalTrials.gov and the US Census Bureau's American Community Survey.^{, c}Broad portfolio site defined as having ≥100 active oncology trials (n = 313 sites). Colors determined by data quintiles.