Press Releases

By Shirley S. Wang
A major long-term study comparing two popular drugs that prevent breast cancer suggests that one, tamoxifen, appears more effective many years after treatment. But both drugs cut high-risk women's risk of developing breast cancer, according to results presented Monday at the American Association for Cancer Research.

The federally funded study of 19,490 women compared those taking an old cancer-prevention drug, tamoxifen, to Eli Lilly & Co.'s osteoporosis drug Evista, generically known as raloxifene, an average of 81 months after the women stopped taking the drug.

In 2006, earlier results published from the study, known as STAR, found that both drugs were equally effective in cutting the risk of breast cancer by 50% in high-risk, postmenopausal women. But women taking tamoxifen had increased risk of certain side effects, like blood clots.

Monday's results suggest that tamoxifen is significantly better at preventing breast cancer than raloxifene. Raloxifene retained only 76% of the effectiveness of tamoxifen in preventing invasive breast cancer, but appeared more effective in preventing non-invasive breast cancer than it did in 2006. In addition, raloxifene users continued to have significantly fewer side effects, including blood clots and uterine cancer, compared with those who took tamoxifen.

"Tamoxifen is still a little bit better," said D. Lawrence Wickerham, one of the study researchers and associate chairman of the National Surgical Adjuvant Breast and Bowel Project, a research network funded by the National Cancer Institute. But, "raloxifene remains an effective way to prevent breast cancer and does it with far less toxicity."

Unless women have a known risk for blood clots or uterine cancer, they can consider both drugs as breast-cancer prevention options, according to Dr. Wickerham, who serves as a consultant to Eli Lilly. Raloxifene may be particularly beneficial for those post-menopausal women with fragile bones because it offers them a "two-for-one benefit" of strengthening bone and preventing breast cancer, he said.

But not all experts agree that raloxifene is just as good an option as tamoxifen.

To read more, visit the Wall Street Journal website.