PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm3 Platelet count at least 160,000/mm3 Hepatic: Bilirubin no greater than 1.0 mg/dL Renal: Creatinine no greater than 1.5 mg/dL Creatinine clearance greater than 65 mL/min Other: Not pregnant Adequate contraception required of all fertile female patients