Clinical trials need diverse participation to thrive
This article first appeared in the St. Louis Beacon, July 31, 2009 - Two cancer patients, one male, one female, get the same treatment. The results should be the same, right? Wrong. The impact of the same medicine can be very different in women and men. But studies that pinpoint those differences don't always include enough women, according to a study published July 15 in Cancer, the journal of the American Cancer Society. The study found women are underrepresented in most clinical trials involving non-gender-specific cancers, such as those found in the lung, colon and brain.
Proper gender representation in any sort of clinical trial happens when researchers include the same women-to-men ratio as the percentage of men and women with the disease. But women have issues that can make including them difficult.
"Women are not usually gauged to be good research subjects because of the menstrual cycle, hormonal considerations and pregnancy," said Dr. Susan Wilson Yang, a doctor of internal medicine with St. Anthony's Medical Center in south St. Louis County, which conducts a small number of clinical trials.
But Washington University's School of Medicine has no problem finding female volunteers. "In our database, women outnumber men 3 to 1," noted Charles Rathmann, the director of the school's Recruitment Enhancement Core. "They don't like to have pregnant women in trials and often they do a urine test to make sure. But that doesn't seem to lower the numbers drastically."
Clinical trials must involve a diverse group of participants if they're funded by the National Institutes of Health (NIH). That includes all but a tiny percentage of those carried out at Siteman Cancer Center, which currently has 256 trials underway.
"We don't see an underrepresentation of women," said Dr. Lannis Hall-Daniels, a radiation oncologist at Siteman.
MINORITY CANDIDATES ARE THE FOCUS HERE
Clinical trials of medications often address two questions: How safe is a drug, and how effective is it? Others compare a new medication to a tested one or test a tried-and-true drug on a different age group. Some aren't focused on drugs at all, but instead investigate diagnostic tools, prevention, screening and quality of life concerns.
Getting a good representation of African Americans, American Indians and other minorities in clinical trials is more of an issue at Washington University and Siteman than gender considerations. Since 2001, African American enrollment in breast cancer studies at Siteman has jumped to 28 percent from 10 percent. This effort to include more minorities is enhanced by the 6-year-old program for the elimination of cancer disparities, which concentrates on breast, lung, prostate, colorectal and cervical cancers -- the most common types.
The increased number of African-American women in breast cancer studies has resulted in an important finding: They are disproportionately affected by a triple negative breast cancer, a condition that does not respond to hormonal therapy, such as the commonly prescribed estrogen inhibitor tamoxifen. Because the discovery is so recent, researchers are scrambling to come up with alternate drugs.
"If we'd had a significant amount of African-Americans participate in clinical trials for the past 20 years, we may have already identified a better treatment strategy for those women a long time ago," Hall-Daniels said. "Now we're racing to find other effective treatments."
THE SIGNIFICANCE OF REPRESENTATION
Awareness of gender in medical research and treatment, whether it involves cancer, heart disease or any other condition, is critical, doctors agreed. "The toxicity or the side effects may be different for men and women," Hall-Daniels said.
Some of the clearest examples can be found in cardiac medications, Hall-Daniels noted. For example, a drug for hypertension and angina, or heart pain, called Posicor was withdrawn from the market after it was found to slow or even stop the heart rate of older women. Three other cardiac drugs are more likely to induce arrhythmia, or irregular heart rate, in women for two reasons: Women experience a longer period of time between heart contractions, and male hormones alter men's sensitivity to the drugs.
Gender bias cuts both ways, Yang said: "I have men in my practice who are being treated for osteoporosis. Many doctors think of it (as) a women's disease, so they don't test men for it."
People in their 80s and 90s of both genders are often underrepresented in clinical trials, said Dr. Paul Hauptman, a professor of cardiology at Saint Louis University. Giving as an example an 82-year-old patient that he would eliminate from a trial, Hauptman said not only would someone her age have more difficulty coming in for regular tests, they would also be more apt to have other conditions such as diabetes and kidney failure, which complicate the findings.
"Am I biased against enrolling her? Yes, but it's not because of her gender; it's mostly because of age and the inconveniences associated with that," Hauptman said.
CLINICAL TRIALS PARTICIPANTS ARE MEDICAL PIONEERS
Often, people who end up participating in clinical trials are barely aware the trials exist until they pick up a pamphlet in their doctor's office. In written material and videos, researchers address the concerns that keep patients from signing up.
"Usually, they fear they're going to be 'experimented on' and we really try to talk to that," Hall-Daniels explained.
Women may not need as much convincing. They tend to trust the health-care system more than men and also tend to volunteer more frequently, in general, Rathmann said.
Participating in clinical trials, which can continue for up to 15 years and require participants to come in at regular intervals for testing, involves a substantial commitment. While volunteers may get some small compensation, they don't do it for the money. According to Rathmann, surveys cite altruism as the main reason. The medical community, and everyone who benefits from it, should be thankful to these volunteers.
"Most of the advancements that have occurred in the last 50 years have come from clinical trials," Rathmann said. "We wouldn't have them if it weren't for this special group of people. They put themselves second and put the betterment of the world first."
Nancy Larson is a freelance writer in St. Louis.