UCSF

Purpose

American minority groups have been historically underrepresented in phase III prostate cancer clinical trials despite often having higher risk disease. We analyzed enrollment trends of major racial/ethnic groups in the United States in phase III prostate cancer trials between 2003 and 2014 compared to SEER (Surveillance, Epidemiology and End Results) incidence data.

Materials and methods

Phase III prostate cancer trials primarily enrolling patients from the United States were identified in the ClinicalTrials.gov database. Enrollment trends were analyzed for major racial/ethnic groups. Prostate cancer incidence data from the SEER registry were used to identify enrollment targets. The enrollment difference was determined by calculating the absolute difference between the percent of a racial/ethnic subgroup in the SEER registry population and the percent of that subgroup in the phase III prostate cancer trial population.

Results

Among 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- -10.5, p <0.001) in 2003 to 2005 and 1.4% (95% CI 0.2-2.6, p = 0.020) in 2012 to 2014. However, African American men were under enrolled in metastatic disease trials (enrollment difference -5.8%, 95% CI -4.8- -6.8, p <0.001). Latino and Asian American men were consistently under enrolled in all trial types.

Conclusions

Minority groups in the United States were largely under enrolled in phase III prostate cancer trials between 2003 and 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.