Assessing the sex-based enrollment gap in urologic oncology clinical trials

Clinical trials should reflect the population affected by the disease under study. While urologic cancers occur more frequently in men, there is still a substantial incidence in women. Ensuring representative enrollment by sex is crucial for trial generalizability, as treatment efficacy and safety may vary between men and women. However, whether women are proportionately represented in urologic oncology clinical trials is unknown.

We estimated the proportion of woman enrollees in bladder and kidney cancer trials with reported results registered on ClinicalTrials.gov since January 1, 2007 through the Aggregate Analysis of ClinicalTrials.gov database. Proportions of woman participants were extracted from result tables, grouped by cancer type, and compared to the proportion of incident cancers occurring in women estimated by the American Cancer Society.

There were 638 cancer trials included in the analysis. The median proportion of women participants in kidney cancer trials was 29% (IQR 23%-38%) compared to an expected proportion of 36% of new kidney cancer cases incident in women, and only 28% of kidney cancer trials met or exceeded 36%-woman participants. Bladder cancer trials enrolled a median 24% women (IQR 17%-33%), similar to the proportion of bladder cancer cases incident in women (24%).

Few kidney cancer trials enroll a representative number of women, while bladder cancer trials enroll as expected. Further work is needed to ensure adequate representation of women in urologic oncology trials to ensure equitable, safe, and effective treatments across sexes.