PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy Chemotherapy: No prior chemotherapy for metastatic disease At least 6 months since prior adjuvant chemotherapy No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiation therapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior major surgery and recovered No concurrent surgery Other: At least 28 days since prior administration of any investigational drug No other concurrent anticancer therapy