PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3 Hemoglobin at least 9 g/dL Platelet count at least 100,000/mm3 No unstable coagulation disorders Hepatic: AST/ALT no greater than 5 times upper limit of normal (ULN) Alkaline phosphatase no greater than 5 times ULN Bilirubin no greater than 2 times ULN Renal: Creatinine no greater than 2.5 mg/dL Cardiovascular: No uncontrolled hypertension or arrhythmias No unstable congestive heart failure Neurologic: No uncontrolled seizure disorder No active neurological disease Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent unstable medical condition (e.g., uncontrolled diabetes mellitus or active infections requiring systemic antibiotics, antivirals, or antifungals)