MONDAY, May 7 (HealthDay News) -- Tamoxifen appears to lower breast cancer risk in women who have undergone hysterectomy, and the benefit is most pronounced in women at high risk of cancer, researchers report in the May 2 issue of the Journal of the National Cancer Institute. However, tamoxifen users may also be more likely to experience hot flashes, thrombi and cardiac arrhythmias or atrial fibrillation.
Umberto Veronesi, M.D., of the Instituto Europeo di Oncologia in Milano, Italy, and colleagues conducted a follow-up analysis of breast cancer rates in 5,408 healthy women after hysterectomy, most of whom were not at elevated risk of cancer. The women were randomized to 20 milligrams of tamoxifen daily or placebo.
Despite earlier study results showing no tamoxifen advantage, the researchers report that after 11 years, tamoxifen users had an annual breast cancer rate of 2.07 per 1,000 women-years compared with 2.48 per 1,000 women-years in the placebo group. The risk ratio was 0.84 for tamoxifen versus placebo, and 0.24 for women at high risk of cancer (6.26 cases versus 1.50 cases per 1,000 women-years). Tamoxifen patients had more hot flashes, thromboembolic events and cardiac problems, including elevated triglycerides and atrial fibrillation.
"Appropriate selection of women at high risk for hormone receptor-positive disease may improve the risk-benefit ratio of tamoxifen intervention," the authors write.
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