Updated Results of the STAR Study of Raloxifene, Tamoxifen Released:
Breast Cancer Prevention Study Confirms Effectiveness of Two Drugs
Cancer Centers of the Carolinas participated in STAR P-2 Trial in Breast Cancer Prevention

Greenville, S.C. (April 19, 2010) – An update of the results of the Study of Raloxifene and Tamoxifen, (STAR P-2 trial in breast cancer prevention) shows that the drug raloxifene (initially used to prevent and treat osteoporosis in postmenopausal women) improved its effectiveness against noninvasive breast cancer, caused significantly less endometrial cancer and was significantly less toxic than tamoxifen. After 81 months of follow-up, although raloxifene was slightly less effective against invasive breast cancer, it still maintained strong efficacy.

Cancer Centers of the Carolinas participated in the STAR Study, one of the largest breast cancer prevention clinical trials ever conducted. STAR enrolled 19,490 postmenopausal women who were at increased risk for the disease in the follow-up study. In South Carolina, 343 women were enrolled state-wide; slightly more than 50% of the South Carolina participants (174 women) enrolled through Cancer Centers of the Carolinas.

This long-term 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, part of the National Institutes of Health.

Participants were randomly assigned to receive either 60 mg of raloxifene (Evista®) (9,754 participants) or 20 mg of tamoxifen (Nolvadex®) (9,736 participants) daily. The 81-month study results (versus the 47 months in the initially published report) show that raloxifene retained 76% of the effectiveness in preventing invasive disease and grew closer to tamoxifen in preventing noninvasive disease, while remaining less toxic. The relative effects of the drugs in the longer term are more consistent with expected profiles, including greater potency of tamoxifen in preventing invasive and noninvasive disease, and, significantly, less endometrial toxicity with raloxifene.

“These results help clarify that both raloxifene and tamoxifen are good preventive choices for high risk postmenopausal women depending largely on a woman’s risk factors,” said Norman Wolmark, MD, NSABP Chairman. “The results of this longer-term study should encourage wide spread acceptance of raloxifene and greater acceptance of tamoxifen for breast cancer prevention among postmenopausal women at an elevated risk, ultimately reducing the burden of breast cancer on the public health.”

Jeffrey Giguere, M.D., served as principal investigator for the STAR trial for Cancer Centers of the Carolinas. Dr. Giguere said, “Nearly 40,000 women deemed at higher risk for breast cancer participated in two national studies determining if that risk could be significantly diminished. The first study found a 50% reduction in a cancer event with tamoxifen versus a placebo (sugar pill). The second study – STAR – randomized a similar at risk population of postmenopausal women between tamoxifen and raloxifene (Evista), the latter drug being FDA approved for the treatment of diminished bone density. What was found was that the raloxifene was equivalent to tamoxifen in reducing the likelihood of a breast cancer event. More importantly, and this is now verified by follow up of over five years, the raloxifene treated population had significantly fewer side effects. Our challenge, frankly, is to get this very positive news to the patients most likely to benefit and to the doctors that see these patients. 40,000 women sacrificed for the sake of making a difference. Their efforts have the potential of making a landmark public health difference.”

Improved detection and treatment of breast cancer have not eliminated the need for better prevention of this disease, which accounted for approximately 192,000 new cancer cases and 40,000 cancer deaths in the United States in 2009. Although the selective estrogen-receptor modulator (SERM) tamoxifen became the first U.S. Food and Drug Administration (FDA) approved agent for reducing breast cancer risk, it did not gain wide acceptance for prevention largely because it increased endometrial cancer and thromboembolic events. Raloxifene was approved by the FDA for breast cancer risk reduction following its pronounced efficacy in preventing invasive, but not noninvasive, breast cancer in the Phase III Study of Tamoxifen and Raloxifene. Initial STAR toxicity profiles favored raloxifene (e.g. significantly reduced thromboembolic events and, non-significantly, reduced endometrial cancer) over tamoxifen. Differences in the two drugs made it imperative to conduct longer-term follow-up to clarify their relative merits in regard to a host of benefits and risks, but particularly in regard to noninvasive breast cancer.

STAR participants were postmenopausal, at least 35 years old and had a modified breast cancer risk as determined by their age, family history of breast cancer, personal medical history, age of first menstrual period and age at first live birth. Eligible women were randomly assigned to receive either tamoxifen or raloxifene daily for five years. Before participating in the Study, women were instructed about the potential risks and benefits of tamoxifen and raloxifene, and then were asked to sign an informed consent document.

Study participant Carole Egly said, “The STAR study was just terrific! It started at just the right time when I needed it. I was diagnosed with LCIS in my left breast in August of 2000. I first read about the study in a magazine. All the exams and visits were on time, the study drug was free and all the people at the Cancer Center were just wonderful.”

These results will be published simultaneously in Cancer Prevention Research, a journal of the American Association for Cancer Research, and a video podcast will be available in the near future.

The makers of tamoxifen, AstraZeneca Pharmaceuticals, Wilmington, Delaware, and the maker of raloxifene, Eli Lilly and Company, Indianapolis, Indiana, provided their drugs and matching placebos for the trial without charge to participants. Eli Lilly and Company, also, gave NSABP support to defray recruitment costs at the participating centers and to help local investigators conduct the study.

For tools used to calculate a woman’s risk for breast cancer, visit http://cancer.gov/bcrisktool.

About Cancer Centers of the Carolinas
Serving Upstate communities for more than three decades, Cancer Centers of the Carolinas (CCC) is a community-based, physician-owned practice with 26 board-certified oncologists practicing in multiple locations across the Upstate of South Carolina. CCC is the Upstate's largest cancer care group treating over 6,000 new patients annually. CCC specializes in medical oncology, radiation oncology, gynecologic oncology, hematology, blood and marrow transplantation and clinical research. CCC is a National Cancer Institute grant recipient and is home to South Carolina's first FACT accredited Stem Cell Transplant Program. For more information on Cancer Centers of the Carolinas, visit www.cancercarolinas.com.

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