PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: Greater than 3 months Hematopoietic: WBC at least 3,000/mm3 Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin within normal range ALT/AST no greater than 2.5 times upper limit of normal (ULN) Renal: Creatinine within 1.5 times ULN AND Creatinine clearance at least 50 mL/min Other: Not pregnant or lactating Fertile patients must use effective contraception No prior malignancy within 5 years and at low risk for recurrence Must have undergone potentially curative therapy for prior malignancy