Geographic Accessibility to Clinical Trials for Advanced Cancer in the United States

Clinical trials yield critical evidence to guide the care of patients with cancer. According to commonly used practice guidelines, “...the best management of any cancer patient is in a clinical trial.”¹ Nonetheless, only about 2% to 7% of US adult patients with cancer participate in clinical trials.² Poor accrual to clinical trials has far-reaching implications in the way it affects the pace of progress, cost of drug development, and generalizability of study findings.

Prior studies exploring trial enrollment have identified several barriers.³ However, geographic barriers to participation in clinical trials remain underexplored. A survey of patients with cancer revealed that most were not willing to travel for trial participation.⁴ We sought to estimate the geographic accessibility of clinical trials for advanced cancer in the United States.

Data regarding clinical trials and associated sites were derived from ClinicalTrials.gov.⁵ We identified all actively accruing trials that evaluated first-line treatments for metastatic breast, prostate, colorectal, and non–small cell lung cancers. Inclusion was limited to these malignant neoplasms because they are the most commonly diagnosed and most frequent causes of cancer death in the United States. Institutional review board approval was waived by Icahn School of Medicine at Mount Sinai.

ClinicalTrials.gov was queried on September 16, 2012, and 227 trials associated with 5011 sites met the criteria for inclusion. The 1-way driving time from each US zip code to the nearest breast, prostate, colorectal, or non–small cell lung cancer trial site was calculated using MapPoint 2013 (Microsoft Corporation). Calculations for each cancer type were performed with each zip code in the contiguous United States as the point of origin and the zip code of the nearest trial site as the destination.

The proportion of patients with metastatic breast, prostate, colorectal, or non–small cell lung cancer residing within x minutes of the nearest trial site was calculated by weighting each origin zip code by the estimated proportion of the total number of people in the United States with metastatic cancer represented within that zip code. Because data regarding the geographic distribution of patients with metastatic disease in the US are not available, we used cancer-specific mortality data (wonder.cdc.gov) to approximate the number and distribution of patients with metastatic disease because most of these patients die of their illness; cancer-related deaths are uncommon at earlier stages of disease.

We found that 45.6%, 50.2%, 52.2%, and 38.4% of patients with metastatic breast, prostate, colorectal, and non–small cell lung cancer, respectively, would need to drive more than 60 minutes 1 way to access a clinical trial site (Table). The Mountain, West North Central, and West South Central regions were generally associated with the longest travel times (Figure).

We found that clinical trials for advanced cancer have poor geographic accessibility for many people in the United States. According to a 2010 Institute of Medicine report, “Sites for clinical trials are frequently selected on the basis of where the investigators are located, as opposed to where the patients are, creating difficulties in patient recruitment.”^6(p21)

There are limitations to our analysis. The minimum travel time that affects the decisions that patients with cancer make about their care is not known. Patients living in metropolitan and rural areas may value travel time differently. We likely underestimated travel time, and many patients will not meet eligibility criteria for the trial that is nearest to them. We also examined the most common cancer types; for rare cancers, trial accessibility is likely worse. We limited our analysis to metastatic cancers. Although travel time is only one aspect of the accessibility of trials, it may be the most important factor for many patients.

Our findings suggest that innovative approaches are needed to improve the geographic accessibility of trials for patients with advanced cancer in the United States.

Corresponding Author: Matthew D. Galsky, MD, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 (matthew.galsky@mssm.edu).

Published Online: December 1, 2014. doi:10.1001/jamainternmed.2014.6300.

Author Contributions: Dr Galsky had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Galsky, Stensland, McBride, Latif.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Galsky, Stensland, McBride, Latif, Moshier.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Galsky, Stensland, McBride, Latif, Moshier, Wisnivesky.

Obtained funding: Galsky.

Administrative, technical, or material support: Galsky, Stensland, McBride, Latif.

Study supervision: Galsky, Oh.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by a Prostate Cancer Foundation Young Investigator Award (Dr Galsky) and a Clinical and Translational Science Award KL2 Faculty Scholars Award (Dr McBride).

Role of the Funder/Sponsor: The funding institutions had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: We thank Ryan Hendricks, BS, Tisch Cancer Institute, for his assistance in compiling data for the current analysis. Mr Hendricks was not financially compensated.