Thirty years have passed since the enactment of the National Institutes of Health (NIH) Revitalization Act, which encouraged NIH-funded investigators to include adequate numbers of women in clinical studies. Since then, there have been important steps taken to ensure better representation of women and racial and ethnic minority groups in biomedical trials. However, lack of representation remains problematic in oncology. Previous research suggests that women represent approximately 30% to 40% of participants in trials leading to drug approvals in the US.

In 2010, the NIH Office of Research on Women’s Health set forth a vision to advance the understanding of sex-specific disease differences by 2020. As clinical trials become international in scope, we sought to evaluate the global movement toward this vision in oncology. In this cohort study, we reviewed enrollment patterns of completed cancer drug trials over the past 20 years to compare sex-specific trial participation to current cancer incidence rates. Using data from the International Agency for Research on Cancer (IARC), we identified 6 common solid tumor types for women (lung, colon, thyroid, melanoma, kidney, and pancreas).