OUTLINE: Randomized study. Following definitive surgical resection, patients are randomly assigned in a 2:2:1 ratio to Arms A, B, and C, respectively. Arm A: Biological Response Modifier Therapy. Interferon alfa-2b (Schering), IFN-A, NSC-377523. Higher dose. Arm B: Biological Response Modifier Therapy. IFN-A. Lower dose. Arm C: Control. Observation.