UCSF Part of Major Breast Cancer Prevention Study

The UCSF Carol Franc Buck Breast Care Center is enrolling volunteers in one of the nation's largest breast cancer prevention clinical trials. Called the STAR trial, for Study of Tamoxifen and Raloxifene for the Prevention of Breast Cancer, the five year study will determine if the osteoporosis prevention drug raloxifene is as effective as tamoxifen in postmenopausal, high risk women. The U.S. Food and Drug Administration (FDA) approved tamoxifen in 1998 for use in breast cancer prevention in high risk women. Factors used to determine risk include age, family history of breast cancer, having children later in life, and a diagnosis of LCIS (lobular carcinoma in situ), a condition that indicates a higher chance of developing invasive breast cancer. The STAR trial will include 22,000 women, enrolled at more than 400 centers across the United States, Puerto Rico and Canada.

"In previous studies, tamoxifen has been shown to significantly reduce the incidence of breast cancer in women who were considered to be at high risk for development of the disease", said Karin Morris, study research coordinator at the UCSF Breast Care Center. Tamoxifen works by interfering with the activity of estrogen, a female hormone that promotes the growth of breast cancer cells. However, tamoxifen can increase a woman's chances of developing endometrial cancer, a cancer which develops in the lining of the uterus.

The FDA approved raloxifene in 1997. It works to increase bone mineral density in the spine, and reduces the risk of spinal fractures in postmenopausal women. Because women taking raoloxifene in the clinical study had fewer breast cancers than women taking a placebo, it is now being studied for breast cancer prevention. Studies of the drug have not shown an increase in the risk of endometrial cancer. An increased risk of developing blood clots has been demonstrated, but this is comparable to the that seen in women receiving estrogen or tamoxifen.

"The goal of the STAR trial is to compare the efficacy of both tamoxifen and raloxifene in the prevention of breast cancer", said Leah Millheiser, M.D., UCSF study coordinator. "The importance of this trial is to provide women at hgh risk with options in terms of breast health, in addition to basic screening techniques such as mammography and clinical breast exams".