Women remain underrepresented in oncology clinical trials, according to a study published in JAMA Oncology.

Researchers analyzed data from 182,416 patients enrolled in 505 oncology trials conducted between 2000 and 2020. Only systemic drug trials were included. All trials had been completed and were registered with ClincalTrials.gov. 

The trials enrolled patients with 6 cancers commonly diagnosed among women: lung, colon, thyroid, kidney, and pancreatic cancers, as well as melanoma.

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Overall, 40% of trial participants were women. Men nearly always outnumbered women, regardless of trial phase, cancer type, time period, or cancer incidence in the female population.

The differences in enrollment between the sexes were significant for all trial phases (P ≤.001) and all cancer types (P <.001) except thyroid cancer (P =.50).

Though women remained underrepresented, there was a “marginal” improvement in female enrollment over time, according to the researchers. The proportion of women enrolled in the trials increased from 40% during 2000-2010 to 42% during 2011-2020 (P <.001). 

The researchers noted that women were underrepresented for all cancer types except pancreatic cancer. For example, 77% of worldwide diagnoses of thyroid cancer are among women, but women made up only 51% of participants in thyroid cancer trials. 

Of worldwide colon cancer diagnoses, 48% are among women, but women made up only 33% of those enrolled in colon cancer trials. On the other hand, women make up 47% of pancreatic cancer diagnoses worldwide, and they made up 47% of participants in pancreatic cancer trials.

Based on these findings, the researchers concluded that “persistent inequities remain in the recruitment of female participants in trials investigating new therapeutics for certain tumor types in oncology.”

Disclosures: One study author disclosed conflicts of interest. Please see the original reference for a full list of disclosures.


Jenei K, Meyers DE, Prasad V. The inclusion of women in global oncology drug trials over the past 20 years. JAMA Oncol. Published online August 26, 2021. doi:10.1001/jamaoncol.2021.3686

This article originally appeared on Cancer Therapy Advisor