Breast Cancer Drug Study Yields Positive Results
New Britain [April 19 2006] -
New Britain General Hospital is Part of National Drug Trial Comparing Tamoxifen and Raloxifene.
Twenty-one New Britain area women were among those participating in an important breast cancer prevention study, whose initial results were announced April 17.
New Britain General Hospital was one 500 study sites in one of the largest breast cancer prevention clinical trials ever conducted. Early results, just released, indicate that an osteoporosis drug, raloxifene, is just as effective as tamoxifen in preventing breast cancer in older, high-risk women.
“This is important news in that we have an effective treatment that is less toxic,” said oncologist Dr. Peter Byeff, the principal investigator for the New Britain General Hospital test center. Dr. Byeff said that 21 women participated through the hospital and that this was a randomized, double blind trial so that neither the women nor the physicians knew which drug they were taking.
“These initial results are an indication of the importance of clinical trials. This is how we make our treatments more effective and less toxic.”
The Study of Tamoxifen and Raloxifene, or STAR, show that the drug raloxifene, currently used to prevent and treat osteoporosis in postmenopausal women, works as well as tamoxifen in reducing breast cancer risk for postmenopausal women at increased risk of the disease. In STAR, both drugs reduced the risk of developing invasive breast cancer by about 50 percent in the nearly 20,000 women who participated in the study.
Women in the study taking raloxifene had 36 percent fewer uterine cancers and 29 percent fewer blood clots than the women who were assigned to take tamoxifen. Uterine cancers have been associated with the use of tamoxifen in the past. Both tamoxifen and raloxifene are known to increase a woman’s risk of blood clots.
The women in this study do not have breast cancer; only an identifiably higher risk for breast cancer by virtue of a number of factors, including family history.
“These are healthy women who had never had breast cancer, so it’s important to have treatments that have as few side effects as possible,” Dr. Byeff said. He stressed that this is a prevention trial, so the results cannot be extrapolated for women already diagnosed with breast cancer.
STAR, one of the largest breast cancer prevention clinical trials ever conducted, enrolled 19,747 postmenopausal women who were at increased risk of the disease. Participants were randomly assigned to receive either 60 mg of raloxifene (Evista®) or 20 mg of tamoxifen (Nolvadex®) daily for five years. The trial is coordinated by the National Surgical Adjuvant Breast and Bowel Project (NSABP), a network of cancer research professionals, and is sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health.
Women taking either drug had equivalent numbers of strokes, heart attacks, and bone fractures. Both raloxifene and tamoxifen are known to protect bone health; it is estimated that half a million postmenopausal women are currently taking raloxifene by prescription to prevent or treat osteoporosis. Additionally, the initial results from STAR suggest that raloxifene does not increase the risk of developing a cataract, as tamoxifen does.
“Although no drugs are without side effects, tamoxifen and raloxifene are vital options for women who are at increased risk of breast cancer and want to take action,” said Leslie Ford, M.D., associate director for clinical research in NCI’s Division of Cancer Prevention. “For many women, raloxifene’s benefits will outweigh its risks in a way that tamoxifen’s benefits do not.”
Participants in STAR are now receiving information about which drug they were taking. Women assigned to raloxifene will continue to receive the drug until they have completed five years of treatment. Those women assigned to tamoxifen can choose to continue taking that or can switch to raloxifene to complete their five years of treatment.
Women who participated in STAR were postmenopausal, at least 35 years old, and had an increased risk of breast cancer as determined by their age, family history of breast cancer, personal medical history, age at first menstrual period, and age at first live birth. Before participating in the study, the women were instructed about the potential risks and benefits of tamoxifen and raloxifene and then were asked to sign an informed consent document.
STAR investigators will present additional data at the 42nd annual meeting of the American Society for Clinical Oncology (ASCO) in June 2006, in Atlanta, GA.
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