Underrepresentation of Racial and Ethnic Minorities in Metastatic Colorectal Carcinoma Clinical Trials within the United States.

Objective: To investigate if underrepresentation of racial and ethnic minorities exists in metastatic colorectal carcinoma (CRC) clinical trials.

Summary background data: Representation of vulnerable subpopulations is essential for generalizability of clinical trials. Limited studies to date have investigated racial and ethnic representation of patients enrolled in clinical trials for metastatic CRC.

Methods: ClinicalTrials.gov was queried for metastatic CRC clinical trials in the United States from 2000-2020. Incidence data were extracted from the SEER Database. Enrollment fraction (EF) was defined as number of trial participants divided by U.S. incidence of metastatic CRC in each race, ethnicity, and gender. Representation Quotient (RQ) was defined as the proportion of trial participants divided by proportion of U.S. metastatic CRC incidence for each subgroup.

Results: 8084 patients from 135 clinical trials were analyzed. 49.6% of clinical trials reported race data and 34.8% reported ethnicity data. Compared to 2000-2009, 2010-2019 had increased representation data reporting for race (61.2% vs. 38.8%) and ethnicity (64.6% vs. 35.4%). Of trials with race data, White patients represented 77.0%, Black patients 6.6%, Asian/Pacific Islander (API) patients 16.1%, American Indian/Alaska Native (AIAN) patients 0.2%, and Hispanic patients 6.8%. Black patients (median RQ 0.54), API patients (median RQ 0.19), AIAN patients (median RQ 0.00), and Hispanic patients (median RQ 0.26) were underrepresented. Black patients had a higher degree of underrepresentation in clinical trials with serum creatinine inclusion criteria (RQ 0.40 vs. 0.86, P=0.034).

Conclusions: Strategies are needed to increase minority enrollment in clinical trials for metastatic CRC. Identification of systemic barriers is integral in public policy advocacy to increase representation.