Raloxifene Lowers Breast Cancer Risk by 72%.

Benefits increase with estrogen exposure.

SAN ANTONIO -- Among women taking raloxifene, those with the highest lifetime exposure to estrogen had the greatest reduction in breast cancer risk.

That was a key finding of an analysis of new data from the Multiple Outcomes of Raloxifene Evaluation (MORE) trial reported at a breast cancer symposium sponsored by the San Antonio Cancer Institute.

The latest follow-up data from MORE indicate that 4 years of raloxifene therapy reduced the risk of all breast cancers by 72%, compared with placebo. The selective estrogen receptor modifier (SERM) reduced the risk of estrogen receptor-positive breast cancers by 84%, said Dr. Marc E. Lippman, professor of medicine at Georgetown University, Washington.

A particularly encouraging new finding was that the higher a woman's lifetime exposure to estrogen--hence, the greater her breast cancer risk--the more potent her breast cancer risk reduction appeared to be with raloxifene, which is indicated for the prevention of osteoporosis in postmenopausal women, Dr. Lippman added.

MORE was a randomized double-blind trial comparing raloxifene with placebo in 7,705 postmenopausal women with osteoporosis. The primary study end point was prevention of fractures, for which raloxifene proved ffective and now has Food and Drug Administration approval. A secondary end point was the incidence of breast cancer.

Asked if he believes the new MORE data give a green light to prescribing raloxifene to prevent breast cancer, Dr. Lippman replied with an emphatic "No."