Researchers announced Tuesday the enrollment of women at 400 medical centers in the United States and Canada for the long-awaited study comparing the drugs Tamoxifen and Raloxifene.
Tamoxifen has long been considered a potent breast cancer treatment. Last year, the Food and Drug Administration approved Tamoxifen as a way to reduce the odds that women at particularly high risk of breast cancer will get the disease.
But Tamoxifen causes serious side effects: It doubled women's risk of uterine cancer, tripled the risk of potentially fatal blood clots and increased chances of developing cataracts.
Raloxifene treats bone-thinning osteoporosis, but studies suggest it could have a similar breast cancer-protecting effect. It, too, has side effects, but doesn't appear to increase the risk of uterine cancer.
The new study, by a research group called the National Surgical Adjuvant Breast and Bowel Project and supported by the National Cancer Institute, will attempt to determine which drug is best.
To find a U.S. study site, call 1-800-4-CANCER; in Canada, call 1-888-939-3333. Or check the National Surgical Adjuvant Breast and Bowel Project or the National Cancer Institute's Cancer Trials Information on the Internet.