Initial STAR results unveiled.

Osteoporosis Drug Raloxifene as Effective as Tamoxifen in Preventing Invasive Breast Cancer

The largest North American breast cancer prevention trial, the Study of Tamoxifen and Raloxifene, or STAR trial, has compiled an initial analysis of study data and found the osteoporosis drug raloxifene works as well as tamoxifen in reducing breast cancer risk for postmenopausal women at increased risk of the disease. Both drugs reduced the risk of developing invasive breast cancer by about 50%.

In addition, within the study, women who were prospectively and randomly assigned to take raloxifene daily, and who were followed for an average of about four years, had 36% fewer uterine cancers and 29% fewer blood clots than the women who were assigned to take tamoxifen. 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.

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. (Read full story.)