Role of anti-aromatase agents in postmenopausal advanced breast cancer

Purpose: Endocrine therapy is a well-recognized approach to the treatment o f postmenopausal patients with advanced breast cancer, particularly those w ith estrogen receptor-positive tumors. The availability of anti-aromatase a gents, both reversible (nonsteroidal) and irreversible (steroidal), provide s clinicians with additional hormonal treatment options. Methods: A MEDLINE search was conducted to identify studies that evaluated anti-aromatase the rapy in the treatment of postmenopausal women with advanced breast cancer. In selecting studies, priority was given to randomized, controlled trials. Results: Tamoxifen is the standard first-line therapy for advanced breast c ancer. However, recent results have demonstrated the efficacy of newer anti -aromatase agents in this setting. Among patients who have progressed after tamoxifen therapy, anti-aromatase agents have emerged as first choice ther apy based on their better tolerability and improved efficacy compared with megestrol acetate. Exemestane and anastrozole (irreversible and reversible anti-aromatase agents, respectively) have demonstrated survival benefits ov er megestrol acetate in second-line therapy. Antiaromatase agents have also demonstrated efficacy in patients who have failed multiple hormonal therap ies. Based on these data, an algorithm for the treatment of postmenopausal women with advanced breast cancer is proposed. Conclusions: The enhanced to lerability and superior efficacy of anti-aromatase inhibitors compared with megestrol acetate has resulted in these agents becoming the endocrine trea tment of choice for women with advanced breast cancer who have progressed a fter tamoxifen treatment. The increased use of tamoxifen in the adjuvant se tting and the demonstrated activity of aromatase inhibitors in first-line t herapy will further increase the role of these agents.