Minority recruitment trends in phase III prostate cancer clinical trials (2003-2014): progress and critical areas for improvement

Abstract

PurposeU.S. minority groups have been historically underrepresented in phase III prostate cancer clinical trials despite often having higher risk disease. This study analyzes enrollment trends of major U.S. racial/ethnic groups in phase III prostate cancer trials between 2003-2014 compared to Surveillance, Epidemiology, and End Results (SEER) incidence data. Materials and MethodsPhase III prostate cancer trials primarily enrolling patients from the U.S. were identified in the ClinicalTrials.gov database. Enrollment trends were analyzed for major racial/ethnic groups. Prostate cancer incidence data from the SEER registry was used to identify enrollment targets. The enrollment difference was determined by calculating the absolute difference between the percentage of a racial/ethnic subgroup in the SEER registry population and the percentage of that subgroup in the phase III prostate cancer trial population. ResultsAmong 39 studies identified, African American enrollment in therapeutic trials increased across the study period (p<0.001). The enrollment difference for African Americans was -9.0% (95% CI, -7.6 to -10.5; p<0.001) in 2003-05 and 1.4% (95% CI, 0.2 to 2.6; p = 0.020) in 2012-14. However, African American men were under-enrolled in metastatic disease trials (enrollment difference = -5.8%; 95% CI, -4.8 to -6.8; p<0.001). Latino and Asian American men were consistently under-enrolled in all trial types. ConclusionsU.S. minority groups were largely under-enrolled in phase III prostate cancer trials between 2003-2014. While recruitment efforts may have had an impact, as demonstrated by increased enrollment of African American men, there remains a need to expand recruitment efforts to achieve diversity in trials.