Aromatase inhibitors in breast cancer: an update.

BACKGROUND Tamoxifen has been the endocrine treatment of choice for patients with breast cancer. The development of selective aromatase inhibitors has offered an alternative management approach for patients in whom a hormonal approach is indicated. METHODS The authors reviewed reports in which aromatase inhibitors were compared with tamoxifen for the treatment of metastatic disease, as well as information pertinent to their use as adjuvant therapy. RESULTS Both nonsteroidal (anastrozole and letrozole) and steroidal (exemestane) aromatase inhibitors for metastatic disease appear to provide superior efficacy and a better toxicity profile in first- and second-line treatment of metastatic disease than tamoxifen. Early results from the ATAC trial suggest anastrozole is superior to tamoxifen for disease-free survival, particularly in receptor-positive patients, and in reducing the incidence of contralateral breast cancer. CONCLUSIONS Aromatase inhibitors have important roles in optimal management of postmenopausal patients with hormone-responsive metastases in both the adjuvant and advanced-disease settings.