Breast cancer prevention: Selective estrogen receptor modulators

Tamoxifen was the first in a series of chemomodulators for use in breast cancer prevention. This selective estrogen receptor modulator (SERM) was studied in 4 pivotal initial trials to assess cancer prevention and side-effect profiles. We will examine these trials and the lessons learned. Raloxifene, though initially approved for the treatment of osteoporosis, has shown promise as well in chemoprevention. Based on preliminary findings in the MORE trial, the ongoing STAR trial will answer further questions about efficacy and side effects. The estrogenic and antiestrogenic side effects of SERMs have enhanced interest in the new generation of aromatase inhibitors. Anastrozole is being studied as an adjuvant therapy in the ATAC trial, wherein side effects and efficacy are compared with those of tamoxifen. To date, it appears that anastrozole may be more effective at reducing the risk of primary, contralateral breast cancer when compared with tamoxifen. Concerns over secondary malignancies, cardiovascular and thromboembolic events, lipid profiles, and bone protection are the issues being addressed in current trials of SERMs and aromatase inhibitors. Chemoprevention issues are ever more important when the concern about hormone replacement therapy and the risks to women's health are prominent areas for discussion in women's health.