Aromatase inhibitors in the treatment and prevention of breast cancer

Purpose: The purpose of this article is to provide an overview of the curre nt clinical status and possible future applications of aromatase inhibitors in breast cancer. Methods: A review of the literature on the third-generation aromatase inhib itors was conducted. Some data that have been presented but not published a re included. In addition, the designs of ongoing trials with aromatase inhi bitors are outlined and the implications of possible results discussed. Results: All of the third-generation oral aromatase inhibitors-lefrazole, a nastrozole, and vorozole (nonsteroidal, type II) and exemestane (steroidal, type I) have now been tested in phase III trials as second-line treatment of postmenopausal hormone-dependent breast cancer. They have shown clear su periority compared with the conventional therapies and are there-fore consi dered established second-line hormonal agents. Currently, they are being te sted as first-line therapy in the metastatic, adjuvant, and neoadjuvant set tings. preliminary results suggest that the inhibitors might displace tamox ifen as first-line treatment, but further studies are needed to determine t his. Conclusion: The role of aromatase inhibitors in premenopausal breast cancer and in combination with chemotherapy and other anticancer treatments are a reas of future exploration. The ongoing adjuvant trials will provide import ant data on the long-term safety of aromatase inhibitors, which will help t o determine their suitability for use as chemopreventives in healthy women at risk of developing breast cancer, (C) 2001 by American Society of Clinic al Oncology.