PATIENT CHARACTERISTICS: Age: 19 to 64 Performance Status: Zubrod 0-3 Hematopoietic: Not specified Hepatic: Bilirubin less than 2 mg/dL SGOT and SGPT less than 3 times normal Alkaline phosphatase less than 3 times normal Renal: Creatinine clearance at least 60 mL/min Cardiovascular: Cardiac ejection fraction at least 50% Pulmonary: No history of severe chronic obstructive lung disease No history of recurrent pulmonary emboli Other: Not pregnant or nursing Effective contraception should be practiced by fertile patients No history of diabetes mellitus complicated by ketoacidosis No history of depression or psychosis No history of autoimmune disorders No concurrent thyroid disorders unable to be maintained on replacement therapy No prior hypersensitivity to interferon alfa-2b