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Results of Nationwide Breast Cancer Prevention Trial Show Osteoporosis Drug Raloxifene is as Effective as Tamoxifen in Preventing Invasive Breast Cancer; Vanderbilt-Ingram Cancer Center is Only Regional Participant

Apr. 17, 2006, 4:57 PM

NASHVILLE, Tenn. – Initial Results of the Study of Tamoxifen and Raloxifene or STAR, released today revealed the osteoporosis drug raloxifene has been proved to be as effective as tamoxifen in preventing invasive breast cancer.

It is one of the largest prevention trials ever conducted, and Vanderbilt-Ingram was the only regional participant. Initial results of the STAR trial 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.

“The results are similar to what I expected. Raloxifene was equivalent to tamoxifen in terms of reducing the risk of invasive breast cancer, and had a more favorable side effect profile in several areas, including endometrial cancer risk, deep vein thrombosis and pulmonary embolus, and cataract risk. It appears that both drugs were equivalent in terms of bone fractures, stroke, heart attack risk and quality of life,” said Mark Kelley, M.D., chief of Surgical Oncology at Vanderbilt-Ingram. “I believe that this makes raloxifene the drug of choice for risk reduction in postmenopausal women at increased risk of developing breast cancer.”

John E. Niederhuber, M.D., with the National Cancer Institute, said the results demonstrate the importance of clinical trials and establishing evidence-based practices. “This optimistic news from STAR is a significant step in breast cancer prevention.”

More than 19,000 postmenopausal women at high risk for developing breast cancer were enrolled in the trial. Vanderbilt-Ingram Cancer Center was one of 400 sites in the United States, Puerto Rico, and Canada who participated in the study. Only five sites in Tennessee enrolled patients in the study, and Vanderbilt is the only hospital in the middle Tennessee region. A total of 58 women were enrolled at Vanderbilt, including a handful of women enrolled at a sub-site at East Tennessee State University in Johnson City. 271 women were enrolled in Tennessee overall. Participants were randomly assigned to receive either 60 mg of raloxifene (Evista®) or 20 mg of tamoxifen (Nolvadex®) daily for five years.

In STAR, investigators said both drugs reduced the risk of developing invasive breast cancer by about 50 percent. 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 percent fewer uterine cancers and 29 percent fewer blood clots than the women who were assigned to take tamoxifen. Researchers said 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.

The trial was coordinated by the National Surgical Adjuvant Breast and Bowel Project (NSABP), a network of cancer research professionals, and was sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health.

The research showed 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.

“Although no drugs are without side effects, tamoxifen and raloxifene are vital options for women who are at increased risk of breast cancer and want to take action,” said Leslie Ford, M.D., associate director for clinical research in NCI’s Division of Cancer Prevention. “For many women, raloxifene’s benefits will outweigh its risks in a way that tamoxifen’s benefits do not.”

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.

Paula Johnston enrolled in the study at Vanderbilt-Ingram. The 57 year-old lost her only sister to breast cancer last year and her mother had two mastectomies fifteen years apart for breast cancer. “Every year the odds get a little bit worse. Everybody I know has someone who has had to deal with it. You don’t have to look too far to find someone,” said Johnston.

She has three daughters, all in their twenties, and her sister left two girls behind when she died. So, Johnston said she felt participating in the STAR trial was important. “I wanted to be a part of it because of all the girls in the family. We don’t know what’s just around the corner.”

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.

Study details include:
• STAR enrolled 19,747 women. This data analysis is based on the 19,471 women for whom complete study information was available.
• The numbers of invasive breast cancers in both groups of women were statistically equivalent. Among the 9,745 women in the raloxifene group, 167 developed invasive breast cancer, compared to 163 of 9,726 women in the tamoxifen group.
• More than half of the women who joined STAR had had a hysterectomy and, therefore, were not at risk of uterine cancer. For those women with a uterus, 36 of 4,732 who were assigned to take tamoxifen developed uterine cancers (mainly endometrial cancer) compared to 23 of 4,712 women who were assigned to take raloxifene.
• In STAR, women in the raloxifene group had 29 percent fewer deep vein thromboses (blood clots in a major vein) and pulmonary embolisms (blood clots in the lung) than women in the tamoxifen group. Specifically, 87 of 9,726 women in the tamoxifen group had a deep vein thrombosis compared to 65 of 9,745 women taking raloxifene. In addition, 54 of 9,726 women taking tamoxifen developed pulmonary embolisms compared to 35 of 9,745 women taking raloxifene.
• The number of strokes occurring in both groups of women was statistically equivalent: 53 of 9,726 women in the tamoxifen group and 51 of 9,745 women in the raloxifene group had a stroke during the trial. There was no difference in deaths from strokes: 6 of 9,726 women in the tamoxifen group and 4 of 9,745 women in the raloxifene group died from this event. Women at increased risk of stroke (those with uncontrolled hypertension or uncontrolled diabetes, or a history of stroke, transient ischemic attack, or atrial fibrillation) were not eligible to participate in STAR.
• While tamoxifen has been shown to reduce, by half, the incidence of lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS), raloxifene did not have an effect on these diagnoses. (LCIS and DCIS are sometimes called noninvasive breast cancers.) Of the 9,726 women taking tamoxifen, 57 developed LCIS or DCIS, compared to 81 of 9,745 taking raloxifene. This result confirms data reported in a large study of raloxifene in the treatment of osteoporosis (the Continued Outcomes Relevant to Evista or CORE Trial) in 2004.

Women who participated in STAR were postmenopausal, at least 35 years old, and had an increased risk of breast cancer as determined by their age, family history of breast cancer, personal medical history, age at first menstrual period, and age at first live birth. Before participating in the study, the women were instructed about the potential risks and benefits of tamoxifen and raloxifene and then were asked to sign an informed consent document.

The maker of tamoxifen, AstraZeneca Pharmaceuticals, Wilmington, Del., and the maker of raloxifene, Eli Lilly and Company, Indianapolis, Ind., 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 more information about STAR, including links to media materials and a fact sheet, visit NCI’s STAR home page at http://www.cancer.gov/star or one of NSABP’s websites at http://www.nsabp.pitt.edu and http://foundation.nsabp.org.

For a Q&A related to the STAR results, go to: http://www.cancer.gov/newscenter/pressreleases/STARresultsQandA.

For B-roll related to the STAR results, go to www.thenewsmarket.com for digitized, downloadable B-roll, or call the NCI Media Relations Branch at (301) 496-6641 for a Beta-tape copy.

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

About the Vanderbilt-Ingram Cancer Center:
The Vanderbilt-Ingram Cancer Center at Vanderbilt University Medical Center is dedicated to a comprehensive, interdisciplinary approach to cancer care, research, prevention, and patient and community education. With nearly 300 investigators, Vanderbilt-Ingram is ranked among the top 10 centers in total research funding from the National Cancer Institute and generates more than $150 million each year in research support from public and private sources. Vanderbilt-Ingram is the only National Cancer Institute-designated Comprehensive Cancer Center in Tennessee and one of only 39 to achieve this distinction nationwide. The center is consistently recognized among the best places for cancer care by U.S. News & World Report. For more information, visit us online at www.vicc.org.

Media Contact: Heather L. Hall, Vanderbilt-Ingram Cancer Center
615-936-7245
Heather.l.hall@vanderbilt.edu

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