Phase III, multicenter, double-blind, randomized study of letrozole, an aromatase inhibitor, for advanced breast cancer versus megestrol acetate

and 2.5 mg every day) and megestrol acetate (40 mg qid) as endocrine therapy in postmenopausal women with advanced breast cancer previously treated with antiestrogens. Patients and Methods: This double-blind, randomized, multicenter, multinational study enrolled 602 patients, all of whom were included in the primary analysis in the protocol. Patients had advanced or metastatic breast can-cer with evidence of disease progression while receiving continuous adjuvant antiestrogen therapy, had experi-enced relapse within 12 months of stopping adjuvant antiestrogen therapy given for at least 6 months, or had experienced disease progression while receiving anties-trogen therapy for advanced disease. Tumors were re-quired to be estrogen receptor – and/or progesteron