Results from 3 clinical trials of tamoxifen to prevent breast cancer have been mixed, with a 50% reduction in incidence seen in a North American . . .
Results from 3 clinical trials of tamoxifen to prevent breast cancer have been mixed, with a 50% reduction in incidence seen in a North American trial but little or no reduction seen in 2 European trials. Investigators now report the first results from the International Breast Cancer Intervention Study, conducted in several European countries (including the U.K.), Australia, and New Zealand.
A total of 7152 women (age range, 35 to 70) who were at high risk for breast cancer were randomized to receive tamoxifen (20 mg daily) or placebo for 5 years. During a median follow-up of 50 months, the breast cancer rate was 32% lower in the tamoxifen group than in the placebo group (69 vs. 101 cancers). However, the rate of thromboembolic events was ab…