DISEASE CHARACTERISTICS: Histologically proven locally advanced or metastatic breast cancer and meeting one of the following criteria: No prior systemic therapy OR Relapsed more than 12 months after stopping adjuvant tamoxifen (tamoxifen- sensitive) OR Relapsed while receiving adjuvant tamoxifen for more than 12 months (tamoxifen-refractory) OR Disease progression while receiving tamoxifen as first-line treatment for metastatic breast cancer (tamoxifen-refractory) Evaluable or bidimensionally measurable disease No rapid disease progression requiring chemotherapy Brain metastases allowed if stable for at least 6 months after surgery or radiotherapy, with no increase in corticosteroids Hormone receptor status: Estrogen receptor positive AND/OR Progesterone receptor positive OR Unknown status allowed if over 50 years old