Researchers in the United Kingdom are concerned about the low level of participation in breast cancer prevention clinical trials. Among women with a high risk of developing breast cancer, the researchers report that only 10% have accepted an offer to participate in clinical trials to determine whether the disease can be prevented with drugs. Another 10% have enrolled in a trial that involves undergoing surgical breast removal (mastectomy) to prevent breast cancer. Meanwhile, a full 60% of the women opted for breast cancer screening instead of preventive action. This worries the researchers who say that it is difficult to achieve preventive strategies for breast cancer without adequate participation in clinical trials.
According to Dr. Gareth Evans of St. Mary’s Hospital in Manchester, England, the low number of women participating in "chemoprevention" trials (studies to determine whether drugs can prevent breast cancer) is reaching a crisis point. Without high levels of participation in clinical trials, the researchers say they cannot determine what is the best way to manage women with a high risk of breast cancer.
Over the past eight years, 4,475 British women at very high risk of breast cancer (40% or more) as determined by family history, etc. have been offered a number of options by the Family History Clinic in Manchester to help prevent the disease. These options include entry into one or two chemoprevention clinical trials, preventive mastectomy, or screening with magnetic resonance imaging (MRI) in addition to annual mammograms. By far, most women chose the MRI screening instead of chemoprevention or mastectomy.
The researchers are particularly concerned about the low enrollment in chemoprevention trials. These trials are important to investigate new drugs that could prevent breast cancer in women at high risk of the disease. However, a drug in a chemoprevention trial may be compared to a placebo (inactive pill) to see if it provides any disease protection. It is the fear of receiving a placebo instead of the real drug that may discourage many women from participating in chemoprevention clinical trials, said Dr. Evans and his colleagues. Women may also worry about side effects from new medications.
Because few women are choosing to participate in chemoprevention trials, the researchers say that these issues need to be addressed. For example, Dr. Evans suggested that the drug tamoxifen (brand name, Nolvadex), which has already been shown to be effective at helping to prevent breast cancer in women at high risk of the disease, be offered to the women who would not receive the new drug in the clinical trials. This way, every woman who participates in a chemoprevention trial receives some type of treatment.
According to an accompanying editorial published in The Lancet, women are underrepresented in other types of clinical trials as well, such as studies of heart disease. It is important to enroll women in clinical trials of every disease that affects them to determine whether there are biological differences in responses to treatments among men and women.
Concerning the low level of participation in British chemoprevention breast cancer trials, the authors of the editorial suggest that women could be influenced by how they are asked to participate in a study. For example, women at high risk of breast cancer may be more likely to enroll in a prevention trial if information about the trial comes from other women who are either at high risk themselves or have undergone treatment for breast cancer. Women also tend to be sensitive to details of the trials, such as the number of breast examinations required.
In 2000, a survey of 6,000 cancer patients revealed that only 2% to 3% of adult cancer patients participate in clinical trials to help test the effectiveness of new treatments. Of the patients surveyed, 84% said they were unaware of the trials or unsure that they would qualify for participation in a trial. Other reasons for low participation included the concern about medical costs, fear that treatment would not be adequate, and the concern of traveling long distances for treatment. However, researchers say that the patients’ physicians can often help ease patient concerns about the cost or quality of care of trials.
In the United States, researchers are currently enrolling 22,000 post-menopausal women at high risk of breast cancer in the STAR (Study of Tamoxifen and Raloxifene) clinical trial. STAR will help determine whether the drug raloxifene (brand name, Evista) is as safe and effective at preventing breast cancer as tamoxifen. Women will receive either raloxifene or tamoxifen; no participants will receive a placebo. Enrollment is taking place at over 500 locations in the United States, Canada, and Puerto Rico.
- The research letter, "Uptake of Screening and Prevention in Women at Very High Risk of Breast Cancer," is published in the September 15, 2001 issue of The Lancet, http://www.thelancet.com/
- The editorial, "Recruitment of Women to Clinical Trials," is published in the September 15, 2001 issue of The Lancet, http://www.thelancet.com/
- The May 30, 2000 Imaginis report, "Too Few Cancer Patients Participate in Clinical Trials, Delaying Advances in Treatment," is available at http://www.imaginis.com/breasthealth/news/news5.30.00.asp
- To learn more about clinical trials, please visit http://www.imaginis.com/breasthealth/clinical_trials.asp
- To learn more about STAR (Study of Tamoxifen and Raloxifene), please visit http://www.imaginis.com/breasthealth/star/
