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U-M Participating in Major Breast Cancer Prevention Trial
originally posted on May 25, 1999
The University of Michigan Comprehensive Cancer Center is taking part in one of the largest breast cancer prevention trials ever.
The Study of Tamoxifen and Raloxifene Â- or STAR Â- will compare two drugs that have shown promise in reducing a person's chance of developing breast cancer. The research study will recruit 22,000 postmenopausal women to determine whether raloxifene, an osteoporosis prevention drug, is as effective in preventing breast cancer as tamoxifen has proven to be.
The primarily government-funded study will be conducted at more than 400 medical centers in North America.
"This is an important trial for many thousands of women and their families around the world," says Sofia Merajver, M.D., Ph.D., U-M's principal investigator and director of the Breast and Ovarian Cancer Risk Evaluation Clinic.
Tamoxifen, a drug that is taken orally in pill form, was approved by the U.S. Food and Drug Administration more than 20 years ago to treat patients with breast cancer. A recent study of more than 13,000 pre- and postmenopausal women showed tamoxifen reduced a person's chance of developing breast cancer by about half. The FDA approved tamoxifen in 1998 to reduce the incidence of breast cancer in women at increased risk for the disease. Tamoxifen works against breast cancer, in part, by interfering with the activity of estrogen, a hormone has been shown to promote the growth of breast cancer cells.
Raloxifene also is an oral medication, taken in pill form. It received FDA approval in 1997 for the prevention of osteoporosis in postmenopausal women. During studies into its ability to prevent osteoporosis, researchers also found that women taking raloxifene developed fewer breast cancers than women taking a placebo did.
"Breast cancer arises over many years. We know that it is, initially at least, a slow-growing disease. From that standpoint, we are trying to find ways of interfering with that growth; we are beginning to see that, in some cases, breast cancer may be preventable," says Merajver.
Participants will be counseled about the potential benefits and risks of the two drugs. Women taking tamoxifen in clinical trials had an increased risk of endometrial cancer, blood clots and stroke. Information on side effects associated with raloxifene is limited because it has not been studied as extensively as tamoxifen. Researchers have found that women taking raloxifene had an increased risk of developing serious blood clots. No link to endometrial cancer was found in previous trials with raloxifene.
Women who are postmenopausal, at least 35 years of age, with an increased risk of breast cancer are eligible to take part in STAR. An increased risk of breast cancer will be determined by a woman's age, family history of breast cancer, personal medical history, age at first menstrual period and age at first live birth.
Women participating in the trial will be randomly assigned to receive either 20 mg tamoxifen or 60 mg raloxifene for five years. Each study subject will take two pills daily. Because the two medications look different, women taking tamoxifen also will take a placebo version of raloxifene while those taking raloxifene will take a placebo version of tamoxifen. The study is double blind, meaning neither the patient nor her doctor will know which medication is being taken. Women in the study also will receive regular examinations, including mammograms and gynecological exams.
Zeneca Pharmaceuticals, the maker of tamoxifen and Eli Lilly, maker of raloxifene, will provide the medications for the trial free of charge. Eli Lilly and Company also will provide funding to defray recruitment costs and to help researchers conduct the study.
For more information about participating in STAR at the University of Michigan or one of its satellite centers, call the U-M Cancer Information Line.
U-M Comprehensive Cancer Center