Older women at higher risk for breast cancer now have two good drug options for preventing the disease, but they will have to weigh the trade-offs, a major study shows.
Tamoxifen, the longtime gold standard, is more effective and longer lasting, the results show. But a newer drug - raloxifene, sold as Evista - is safer.
"I don't see a clear winner," but two good choices with different risks and benefits, said Dr. Scott Lippman, a cancer specialist at the University of Texas M.D. Anderson Cancer Center. He is editor of Cancer Prevention Research, a journal that published long-term results from the federally funded study Monday.
Tamoxifen is widely used to treat cancer once it's diagnosed, and Evista is used to treat osteoporosis. But the drugs have not found wide acceptance so far as cancer preventives. Doctors hope the findings will spur more high-risk women to consider taking one of the drugs.
They're not recommended for women at average risk of breast cancer. But for the millions who are at higher risk because of gene mutations, family history or other factors, they can make a dramatic difference.
Tamoxifen cut the chances of developing the most serious forms of breast cancer in half, the research shows, but with a higher risk of uterine cancer. Evista cut the cancer risk by 38 percent, with fewer uterine problems and other serious side effects.
Tamoxifen has long been used to treat and prevent breast cancer. It blunts estrogen, which fuels the growth of most tumors that occur after menopause.