Closing the Gender Gap in Cancer Research

July 12, 2013

Women are under-represented in cancer studies, a bias that has concerned researchers for years yet has gone largely unaddressed.

Lower participation rates by women in health studies generally results in their not getting the same access as men to the latest treatments, and may also deny researchers important information about how new therapies will work. That has led two oncologists at Cedars-Sinai Medical Center in Los Angeles to establish Research for Her, a local online registry that went live in March. 

The immediate goal is to register at least 2,000 women to participate in studies on breast or gynecological cancers. Both ill and healthy patients are needed for comparison purposes. The principals hope eventually to expand the effort into a national registry and identify women eligible for cancer studies across the country. So far, 185 women have registered.

Dr. Catherine Dang (picture on the right), a breast cancer specialist behind the registry effort, said many women are deterred by the notion that they will become mere guinea pigs for the latest experimental treatments.

“I always explain that they can withdraw at any time and that your rights are protected in terms of making sure your health is not injured in any way,” she says. “I tell them they are doing something for the greater good and not just for their immediate benefit. Science can’t progress without participation in clinical trials.” 

 There is a long history of excluding female subjects from clinical trials, starting with the laboratories that test treatments on animals.

“With females, there’s pre-menopause, post-menopause, there’s menopause and when you throw all that into the mix, it makes for less of a clean study,” Dang says. “That’s why it’s easier to study people who don’t have all these hormonal changes … hormones can dramatically change a stress response, so it makes the study more challenging.” 

The bias toward men in health studies is deeply ingrained, says Dr. Reshma Jagsi, an associate professor in the department of Radiation Oncology at the University of Michigan Health System, who has studied the issue extensively. She says women are under-represented in most areas of medical inquiry, including heart disease.

“We were trained to do everything on the 70 kilogram male in medical school,” she says, calling the gender bias “a major missed opportunity” in understanding disease mechanisms and the viability of new treatments. 

Jagsi once looked at a year’s worth of major cancer journals to measure women’s participation in hundreds of cancer studies. Among non-sex specific cancer types, the mean percentage of women subjects was 38.8 percent. For cancers where the prevalence of women victims is high, they were similarly under-represented.

Jagsi found that less than one-third of lung cancer study participants were women, even though women make up roughly half of lung cancer diagnoses.

Women also perceive a greater risk tied to joining a clinical trial, as compared with men. A study published in the Archives of Internal Medicine in May 2007 concluded that women were more concerned than men about the risk of harm to their health in cardiovascular prevention trials, and were less willing to participate.

In my own case, in which a cancerous tumor was found in my lung earlier this year, I was asked if I’d be interested in participating in a clinical trial that added a COX-2 inhibitor, a form of a non-steroidal anti-inflammatory, to standard treatment,  and decided to hold off. Part of the reason I don’t want to do it is because I’d have to get to the University of Chicago in Hyde Park — a 45 minute drive — to participate. 

No follow-up analysis has been done since Jagsi published her findings in a July 2009, issue of the journal Cancer. She believes little has changed except in cases where financial incentives were offered to female participants, who are more likely to be juggling their health needs with taking care of family members.

Interestingly, the U.S. National Institutes of Health states explicitly that women be encouraged to participate in clinical trials.

“When a researcher proposes a study, why not include in the grant some small amount of dedicated funding to reimburse female participants for the care of a child or parent? Something that simple and straightforward could boost female participation,”  Jagsi says.

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Thanks for pointing out how women aren’t well represented in cancer studies, something that is also true for so many diseases. Very informative!

Posted by laurieu | Report as abusive

Working in clinical research I have noticed there is a big push to enroll women in clinical trials, however in most of these cases it’s just right place at the right time. I don’t think investigators are out there looking for female participants.

Posted by Britwife | Report as abusive

Through out health care there is an under representation of women. Part of the issue is that women are asked to be using 2 forms of birth control for many studies. There is also a huge time commitment and issues such as childcare and transportation are not taken into account. Good to see that there is more dialog going on about this.

Posted by nancyrg | Report as abusive