One of the largest breast cancer prevention studies ever conducted shows an osteoporosis drug has fewer side effects and is as effective as tamoxifen in preventing breast cancer.

Results released in April 2006 show raloxifene, used to prevent and treat the bone-thinning condition, works as well as tamoxifen in reducing breast cancer risk for postmenopausal women at increased risk of breast cancer.

The nationwide study, which included 202 women enrolled by The University of Iowa at six sites, showed both tamoxifen and raloxifene reduced the risk of developing invasive breast cancer by about 50 percent.

Women assigned to take raloxifene also had 36 percent fewer uterine cancers and 29 percent fewer blood clots than women assigned tamoxifen.

“Ultimately, if we can’t find a fix for breast cancer, maybe we can find a prevention,” said Mark Karwal, MD, a University of Iowa co-investigator on the study. “This is one of those baby steps.”

--Tom Moore