Purpose: Many cancer clinical trials lack appropriate representation of specific patient populations, limiting their generalizability. Therefore, we determined the representation of ethnic minorities and women in cancer clinical trials.
Methods: Enrollment data from all therapeutic trials reported as completed in ClinicalTrials.gov from 2003 to 2016 were analyzed. We calculated enrollment fractions (EFs) for each group, defined as the number of enrollees divided by the 2013 Surveillance, Epidemiology, and End Results (SEER) database cancer prevalence.
Results: Of 1,012 clinical trials, 310 (31%) reported ethnicity with a total of 55,689 enrollees. Participation varied significantly across ethnic groups. Non-Hispanic whites were more likely to be enrolled in clinical trials (EF, 1.2%) than African Americans (EF, 0.7%; P < .001) and Hispanics (EF, 0.4%; P < .001). A decrease in African American (6% v 9.2%) and Hispanic (2.6% v 3.1%) enrollment was observed when compared with historical data from 1996 to 2002. Younger patients (age younger than 65 years) were more likely to be enrolled in clinical trials than the elderly (64% v 36%; P < .001). Low recruitment of female patients was observed in clinical trials for melanoma (35%), lung cancer (39%), and pancreatic cancer (40%).
Conclusion: We observed a decrease in recruitment of minorities over the past 14 years compared with historical data. African Americans, Hispanics, and women were less likely to be enrolled in cancer clinical trials. Future trials should take extra measures to recruit participants that adequately represent the US cancer population.