A new study finds that the racial composition of clinical trials involving radiation therapy does not match that of the U.S. population. Examining trials from the past 23 years, researchers found that roughly 12% of trial participants were Black, which is less than the 13% of African Americans in the U.S. census and does not account for disproportionately higher rates of cancer incidence and death among African Americans.
Asian American patients were also underrepresented in the trials relative to their population size. Findings were presented last week at the American Society for Radiation Oncology (ASTRO) Annual Meeting.
“Clinical trials should reflect the diversity that exists in a population, yet we know challenges exist in both recruitment and retention of trial participants from racial minority groups,” said Emily H. Bero, a medical student at the Medical College of Wisconsin in Milwaukee and lead author of the study. “Understanding and minimizing disparities in clinical trials is critical to ensure health equity and the generalizability of research findings.”
While the new study looks specifically at representation in radiation therapy trials, enrollment data from cancer trials in general indicate that inclusion of patients from racial/ethnic groups in those studies has gotten worse over time.
For the current analysis, researchers examined clinical trials involving radiation therapy that were posted from 1996 to 2019 on ClinicalTrials.gov. A total of 122 trials (of 1,242 reviewed) met inclusion criteria, and researchers compared the percentages of different race groups in those trials to U.S. census estimates from 2018.
“We were surprised that the percentage of patients who are Black was not much lower than the census in terms of raw percentages, given the disparities and barriers that Black patients face in regard to clinical trials,” said senior author William A. Hall, MD, an associate professor of radiation oncology and surgery at the Medical College of Wisconsin. “There is still work to do in this regard, however, especially because some types of cancer disproportionately affect Black patients.”
The underrepresentation of Asian American patients was also surprising, Hall said. “Asian Americans have not been discussed extensively in research on disparities in clinical trial participation, but our findings signal that these discussions are needed,” he noted.
Next steps for the researchers include expanding their focus to additional reasons behind the disparities, such as socioeconomic status or characteristics of the trials themselves. Structural racism, distrust of medical providers, hidden costs associated with trial participation, and a lack of community outreach by researchers are recognized as limiting inclusion of patients from underrepresented minority groups in cancer clinical trials.
Edited by Gary Cramer