April 7, 2006
The Tulane Cancer Center participated in one of the largest breast cancer prevention trials ever conducted. Initial results of the Study of Tamoxifen and Raloxifene (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 addition women in the study who were randomly assigned to take raloxifene daily, and who were followed for an average of about four years, had 36 percent fewer uterine cancers and 29 percent fewer blood clots than the women who were assigned to take tamoxifen, says Roy Weiner, director of the Tulane Cancer Center, who was the principal investigator for the study at Tulane.
Uterine cancers, especially endometrial cancers, are a rare but serious side effect of tamoxifen. Both tamoxifen and raloxifene are known to increase a woman's risk of blood clots. STAR enrolled 19,747 postmenopausal women who were at increased risk of the disease. At Tulane, about 80 women living in Louisiana and along the Gulf Coast were enrolled in the study. 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.
"In 1998, the landmark Breast Cancer Prevention Trial showed that tamoxifen could reduce the risk of invasive breast cancer in premenopausal and postmenopausal women by nearly 50 percent. Now we know that for postmenopausal women at increased risk of breast cancer, raloxifene is just as effective, without some of the serious side effects known to occur with tamoxifen," Weiner says.
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.
Women who participated in STAR were postmenopausal, at least 35 years old, and had an increased risk of breast cancer as determined by factors such as their age, family history of breast cancer and personal medical history. The STAR researchers also tracked known menopausal side effects that occur with both drugs and monitored the participants' quality of life. The data show that side effects of both drugs were mild to moderate in severity, and quality of life was the same for both drugs.
Participants in STAR are now receiving information about which drug they were taking. Women assigned to raloxifene will continue to be provided with the drug until they have completed five years of treatment. Those women assigned to tamoxifen can choose to continue taking tamoxifen or to receive raloxifene to complete their five years of treatment.
For more information about STAR, including links to media materials and a fact sheet, visit NCI's STAR home page.
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