PATIENT CHARACTERISTICS: Age: 18 and over Performance status: 70-100% Karnofsky Hematopoietic: Absolute neutrophil count at least 1,000/mm3 Platelet count at least 50,000/mm3 Hemoglobin at least 8 g/dL Hepatic: Not specified Renal: Not specified Other: Neurologic status 0-2 No major medical or psychiatric contraindication to protocol entry Fertile patients must use effective contraception