An evaluation of trends in the representation of patients by age, sex, and diverse race/ethnic groups in bladder and kidney cancer clinical trials

Abstract

Objectives: To determine the representation of women, minorities, and the elderly groups in clinical trials and whether participation has changed over time.

Methods: Retrospective study in the National Cancer Institute (NCI) Clinical Data Update System and Center for Disease Control and Prevention United States Cancer Statistics 2000 to 2019. We compared cancer incidence proportion to proportion of patients enrolled in an NCI trial when stratified by race/ethnicity, sex, and age. We performed multivariable analysis to determine the odds of participating in a clinical trial in 2015 to 2019 when compared to 2000 to 2004.

Results: This study included 14,094 patients, 12,169 (86.3%) non-Hispanic White patients, 662 (4.7%) Black patients, and 660 (4.7%) Hispanic patients. There were 3,701 (26.3%) female patients and 10,393 (73.7%) male patients. For bladder cancer clinical trials, Black patients and Hispanic patients were underrepresented in clinical trials compared to Non-Hispanic White patients (odds ratio [OR] 0.71, 95% confidence interval [CI] 0.57-0.88, P = 0.002) and (OR 0.69, 95%CI 0.54-0.88, P = 0.003), respectively. For kidney cancer trials, Black and Hispanic patients were underrepresented in clinical trials compared to Non-Hispanic White patients (OR 0.42, OR 0.33-0.54, P < 0.001) and (OR 0.68, 95% CI 0.55-0.83, P < 0.001), respectively. Women were underrepresented in kidney cancer trials compared to men (OR 0.80, 95% CI 0.72-0.89) and similarly for bladder cancer trials (OR 0.72, 95% CI 0.64-0.81, P < 0.001). For bladder cancer trials, the participation of Black patients over time (OR 1.04, P = 0.814) and female patients over time (OR 1.03, P = 0.741) were unchanged. For kidney cancer trials, the participation of Black patients over time (OR 1.17, P = 0.293) and female patients over time (OR 1.03, P = 0.663) participation was also unchanged.

Conclusion: In this study of clinical trials in bladder and kidney cancer, we identified that Blacks, Hispanics, and females were underrepresented. Additionally, Black and female participation was unchanged over the span of 20 years.

Keywords: Bladder cancer; Clinical trials; Health services research; Kidney cancer.