Tamoxifen, raloxifene cut breast cancer risk in half

Reported April 20, 2010

Two drugs taken by women at high risk for breast cancer — tamoxifen and raloxifene — both reduce the risk of the disease by about 50% in high-risk post-menopausal women while they are taking the medications, researchers said Monday. The benefits of raloxifene fall off more quickly once women stop taking them, however, and the increased benefits of tamoxifen come at a price: a higher risk of uterine cancer, blood clots and cataracts — although the absolute risks of all three remain low.

"These are relatively inexpensive drugs that reduce breast cancer by about 50% with side effects that are modest," said Dr. Gabriel N. Hortobagyi of the University of Texas M.D. Anderson Cancer Center in Houston, one of the researchers. "We need to reassess why we are not using these drugs more broadly," he said at a news conference at a meeting of the American Assn. of Cancer Research, where the results were presented.

The new results represent an extension of a clinical trial that was first reported in 2007 and allow refinement of the researchers' earlier conclusions. But the basic message is that women can confidently take either drug to sharply reduce their risk of dying from breast cancer.

"If they can't tolerate their first choice, they can take advantage of the second drug," said Dr. Larry Wickerham of Allegheny General Hospital in Pittsburgh, another researcher on the team.

The trial enrolled 19,747 post-menopausal women over the age of 35 who had an above-normal risk of breast cancer because they had breast cancer genes or a family history of the disease. While the average 60- to 64-year-old woman has about a 1.66% risk of developing breast cancer over a five-year period, the women in the study averaged twice that risk, and some had an even higher risk. (Women can calculate their own risk at http://www.cancer.gov/bcrisktool

Women who had uncontrolled diabetes or hypertension were excluded from the trial, as were those at a high risk for stroke or blood clots.

The women were given either tamoxifen (brand name Nolvadex, also available generically) or raloxifene (brand name Evista) daily for five years.

Source : The Los Angeles Times