DISEASE CHARACTERISTICS: Histologically or cytologically proven breast cancer Must be enrolled no later than 40 weeks from the start of first line chemotherapy for metastatic disease High dose chemotherapy with bone marrow transplantation or stem cell rescue as part of first line therapy is allowed Either no evidence of disease or nonprogressive disease following first line chemotherapy Patients receiving concurrent hormonal therapy are eligible Patients with bone metastases as the only site of disease are eligible No known brain metastases (patients with stable brain metastases for greater than 6 months may be allowed if not on concurrent corticosteroids) No locoregional disease as the only evidence of metastases Hormone receptor status: Not specified