Nationwide Breast Cancer Prevention Trial Resuts 4-18-2006
The Preston Research Building, Home of Vanderbilt-Ingram Cancer Center
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.
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
She has three daughters, all in their twenties, and her sister left two girls behind when she died. So,
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.
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 Web sites at http://www.nsabp.pitt.edu and http://foundation.nsabp.org.
For a Q&A related to the STAR results, go to:
Heather L. Hall