PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy for advanced/metastatic disease At least 4 weeks since prior adjuvant chemotherapy Endocrine therapy: See Disease Characteristics No more than one prior progestational hormone therapy regimen for advanced/metastatic disease At least 1 week since prior hormonal therapy No prior tamoxifen or other aromatase inhibitor therapy Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy Concurrent radiotherapy for symptomatic metastatic lesions allowed Surgery: See Disease Characteristics Other: No other concurrent anticancer therapy No other concurrent investigational therapy