Historically, medical research has focused on white men rather than women or people of color, says Nicole Woitowich, PhD, research assistant professor of medical social sciences at Northwestern University Feinberg School of Medicine.
This has changed somewhat in recent years, following a push for greater gender and minority representation in clinical studies, including draft guidance from the Food and Drug Administration (FDA). Still, disparities remain.
In 2018, only 38% of participants in cancer trials were women, according to the FDA. Black and Latino people each constituted only about 4%, though they represent 13% and 18% of the U.S. population, respectively. Also, most participants in trials are under the age 65.
Reasons for lack of minority representation include lack of access to transportation, mistrust of the medical establishment, researcher bias, and lower-income, which can make it difficult to pay for transportation to appointments or for childcare.
For women, paternalism was a factor in the past, Woitowich says, along with concerns about including women of childbearing age in clinical trials. While more women are being included now, research results are often not separated and analyzed by gender, she says. This makes it difficult to tell if women and men are responding to drugs in the same way.
Responses to cancer treatment can vary by sex, race, and ethnic heritage. For example, nonwhites are more likely to have side effects from a common chemo drug, fluorouracil. Women tend to have more adverse medication reactions in general than men, Woitowich says.
“Until we start having these more rigorous and robust studies where data are analyzed by sex, we’re really failing half of the population,” Woitowich says.