PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm3 Hemoglobin at least 10 g/dL Platelet count at least 160,000/mm3 Hepatic: Bilirubin no greater than 1.0 mg/dL AST no greater than 1.5 times upper limit of normal (ULN) Alkaline phosphatase no greater than 5 times ULN Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance at least 50 mL/min Cardiovascular: No unstable cardiac disease requiring treatment Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No other concurrent active cancer No history of significant neurologic or psychiatric disorders, including psychotic disorders, dementia, or seizures No active uncontrolled infection No other serious illness or medical condition