Abstract A71: Clinical trial participation: Differences in distance traveled across different ethnic groups
Authors: Yeager Katherine A. , Bruner Jesse , Pugh Stephanie L. , Bruner Deborah Watkins 
Published: May 2015

Background: Latinos and African Americans make up a significant portion of the U.S. population, and face either high prevalence and/or high morbidity related to cancer compared to Whites but cancer clinical trial participation rates continue to be low. Multiple barriers have been identified including travel distance but little work has assessed differences between ethnic groups. The purpose of this analysis was to examine the distance between participants' home zip codes and the Radiation Therapy Oncology Group (RTOG) site where they participated in a clinical trial and look for differences between types of sites and racial/ethnic identification.

Methods: Data was obtained from RTOG, including zip codes of RTOG full and affiliate members and their satellite sites along with Community Clinical Oncology Program (CCOP) members. In addition, patient accrual to all RTOG clinical trials per site over the period of 2006-2009 was collected. Patient data collected included zip code, race, and ethnicity only. Only patients with complete data were included. Racial/ethnic categories included Latino, African American, and other. The other category included 96% Whites and was subsequently labeled Whites. No additional identifiers were collected. Next the distance (direct distance in miles) was calculated between the centroid of the U.S. postal zip codes of all individual patients and the RTOG site address where the patient was accrued. Descriptive statistics were calculated for distance traveled for the different types of sites and the three ethnic categories (African American, Latino and White).

Results: Of the total sample size of 6168 patients, 80% had complete information and were included in the analysis. 4072 were treated at full/affiliate site and 841 at a CCOP site. Of those patients who participated in a full or affiliate site, 11% were African American and 4.1% were Latino with the remainder being White. Similarly of those who participated at a CCOP site, 11.4% were African American and were 4.5% Latino. Concerning distance traveled to different types of sites, travel to full/affiliate membership sites was greatest for Whites (median 13.4 miles) and least for African Americans (median 5.75 miles). Whites and Latinos traveled a significant greater distance to a Full/Affiliate sites compared to a community sites (p&lt;0.0001 and p=.01 respectively) whereas African American's travel distance to Full/Affiliate or community sites was not significantly different (p=0.60). Per post hoc analysis, White patients traveled significant longer than African American or Latinos patients to community sites (p&lt;0.0001, p=0.001, respectively). For full/affiliate sites (non-community), African Americans traveled a significantly shorter distance when compared to Latinos or Whites (p&lt;0.0001 for both).

Conclusion: Distance traveled to participate in clinical trials is an area which requires consideration especially in radiation treatment trials. Different racial/ethnic groups experience different travel burden sometimes based on where they live. For urban dwellers, factors such as public and private transportation options including access to private car, bus and rail routes, bus and rail stops, transfers, walk times and wait times are important to consider in addition to distance. For rural residents, distance traveled and economic factors, such as gas prices are important. With a greater understanding of travel burden for clinical trial participants, we can alter outreach efforts to include more minorities in cancer clinical trials to help improve treatment outcomes.

(This study was supported by the Pennsylvania Commonwealth Universal Research Enhancement (C.U.R.E.) Program ME-02-149, RTOG U10 CA21661 and CCOP U10 CA37422 grants from the NCI.)

Citation Format: Katherine A. Yeager, Jesse Bruner, Stephanie L. Pugh, Deborah Watkins Bruner. Clinical trial participation: Differences in distance traveled across different ethnic groups. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr A71. doi:10.1158/1538-7755.DISP13-A71