Abstract
Selective estrogen receptor modulators (SERMs) reduce the risk of recurrence of invasive breast cancer and the incidence of first breast cancers in women who are at increased risk. Multiple, randomized clinical trials have shown both the efficacy and safety of SERMs in reducing the risk of breast cancer. Long-term follow-up as long as 20 years in the randomized trials shows persistent efficacy with acceptable safety. Hormone replacement therapy given concurrently with tamoxifen abrogates its preventive effect, but women with atypical hyperplasia derive particular benefit from SERM therapy. Aromatase inhibitors also reduce the risk of developing invasive breast cancer, but the experience with them for risk reduction is limited to few trials. National organizations have made recommendations to use SERMs and aromatase inhibitors to reduce the risk of breast cancer in high-risk women and additional efforts should be made to increase their use in clinical practice, where the number of women needed to treat to prevent one case of breast cancer conforms to accepted standards of preventive medicine.