PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 3 months Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Hemoglobin at least 9 mg/dL (may be post transfusion) Platelet count at least 100,000/mm3 Hepatic: Bilirubin normal SGOT/SGPT no greater than 2.5 times upper limit of normal PT/PTT normal Renal: Creatinine no greater than 1.5 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active infection requiring parenteral antibiotics No documented abnormal CNS exam with seizure disorder or major neuropsychiatric problems