PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: Not specified Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 2 times upper limit of normal (ULN) Alkaline phosphatase less than 2.5 times ULN if SGOT is greater than 1.5 times ULN Renal: Creatinine no greater than 2.0 mg/dL Other: No other malignancies within the past 5 years except curatively treated basal or squamous cell skin cancer or carcinoma in situ of the cervix or breast Not pregnant or nursing Fertile patients must use effective contraception