PATIENT CHARACTERISTICS: Age: Not specified Performance status: WCCC 0-2 Life expectancy: At least 3 months Hematopoietic: WBC at least 3000/mm3 Absolute neutrophil count at least 1200/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 8 g/dL Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 2.5 times normal Renal: Creatinine no greater than 1.5 times upper limit of normal Other: At least 5 years since prior malignancy other than: Inactive nonmelanoma skin cancer Adequately treated stage I or II cancer in complete remission No other serious illness No spinal cord compression symptoms