October 23, 1998

VCC to test potential breast cancer breakthrough

VCC to test potential breast cancer breakthrough

The Vanderbilt Cancer Center is the only center in the region that will take part in the second study of a potential new prevention for breast cancer, set to begin next spring.

The Study of Tamoxifen and Raloxifene (STAR) comes on the heels of the first breast cancer prevention trial, which demonstrated a decrease in incidence of invasive breast cancer in high-risk women who took the estrogen-blocking drug tamoxifen. STAR will examine whether a tamoxifen-like drug called raloxifene is also effective at preventing breast cancer and whether it offers any benefits over tamoxifen.

"The Vanderbilt Cancer Center is very interested in 'chemo-prevention' of cancer," said Dr. Mark C. Kelley, assistant professor of Surgery and clinical director of the Vanderbilt Breast Center.

Kelley is the principal investigator of STAR at the Vanderbilt Cancer Center. "This is an important study because, although the results of the first trial with tamoxifen were statistically significant, more research in this area is needed."

The first study, the Breast Cancer Prevention Trial (BCPT), was launched after laboratory and clinical work with tamoxifen suggested that it could reduce the occurrence of breast cancer. The study enrolled more than 4,000 post-menopausal women considered at high risk for breast cancer because they were over age 65, had a family history of breast cancer or a benign breast condition that put them a high risk for developing breast cancer. Half were randomly assigned to receive tamoxifen, while the other half received a placebo.

The study was designed to examine the data after three years. Last year, the data was examined and the researchers found that the group taking tamoxifen had a 49 percent decrease in the incidence of invasive breast cancer compared to the group taking the placebo. The study was stopped, the women on placebo were offered tamoxifen, and FDA approval of the drug for prevention of breast cancer was recommended. Other studies in Great Britain and Europe, conducted in slightly different patient groups, have not shown similar prevention benefits.

STAR will compare tamoxifen with raloxifene, a drug developed as a treatment for osteoporosis. "Raloxifene can either activate or block estrogen under different circumstances and in different tissues," Kelley explained. "It was developed to work like estrogen to protect bone mass but not affect the uterus and breast. Researchers found that it works almost as well as estrogen for osteoporosis without affecting the endometrial lining of the uterus, but they also noticed a reduction in breast cancer incidence."

STAR will enroll 22,000 post-menopausal women age 35 or older who are considered at high-risk for breast cancer based on criteria similar to the tamoxifen study. Participants will be randomly assigned to receive 20 milligrams of tamoxifen or 60 milligrams of raloxifene daily for five years. They will be closely followed, with regular physical and gynecologic examinations and mammograms, for at least seven years.

Like the first study, STAR is designed and coordinated by the Pittsburgh-based National Surgical Adjuvant Breast and Bowel Project (NSABP). So far, nearly 200 centers have been selected to participate in STAR. The Vanderbilt Cancer Center, a National Cancer Institute-designated center, is the only institution in Middle Tennessee selected to participate.

STAR is supported by the NCI and the pharmaceutical companies that make tamoxifen and raloxifene. Both drugs will be offered at no charge to participants.

The study will not begin until early next year, but women who would like to receive information about the trial as it becomes available can do so by contacting the NSABP. The mailing address is Box 21, Pittsburgh, PA 15261. The NSABP may also be contacted by fax at (412) 330-4660 or through the internet at www.nsabp.pitt.edu.