The Food and Drug Administration advisory panel has preliminarily approved the drug Raloxifene (Evista) as a form of chemoprevention for women at high risk for breast cancer. Post-menopausal women who had an increased five-year risk for breast cancer were the subjects of the study. Using Raloxifene for chemoprevention is considered an expanded option for the drug, originally intended for treating osteoporosis.
In 1998, Tamoxifen (Nolvadex) was approved as the first chemoprevention drug for breast cancer. This drug carried potentially serious side effects such as endometrial cancer and deep-vein thrombosis. The clinical trial STAR, Study of Tamoxifen and Raloxifene, compared the ability of the two drugs to reduce rates of breast cancer in postmenopausal women at high risk for the disease. The results showed that both drugs lowered breast cancer incidence by about 50%, but Raloxifene did so with a significantly lower incidence of side effects. This is an important finding in light of the fact that many doctors and patients have opted out of Tamoxifen treatment due to its side effects, and many doctors are already familiar with Raloxifene because they prescribe it for osteoporosis prevention and treatment (see ACSH's What's the Story? Weighing the Benefits and Risks of Your Medications).
This STAR trial was done by the National Surgical Adjuvant Breast and Bowel Project (NSABP). Findings of the STAR trial and of other future planned projects, such as the recently canceled study comparing Raloxifene to the aromatase inhibitor Letrazole, are crucial. However, it is also important to determine who is at high risk for breast cancer so that Raloxifene and other chemoprevention drugs can be prescribed more accurately, avoiding unnecessary side effects.
Let us hope the FDA approves Raloxifene when the agency votes in a few months, allowing women and their doctors to decide when to use this drug.
Krystal Wilson is a research intern at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).
See also: ACSH's Chemoprevention of Breast Cancer.
