Chemotherapy, Interferon Alfa, and Radiation Therapy in Treating Patients Who Have Undergone Surgery For Pancreatic Cancer

RATIONALE: Drugs used in chemotherapy, such as cisplatin and fluorouracil, use different ways to stop tumor cells from dividing so they stop growing or die. Biological therapies such as interferon alfa may interfere with the growth of the tumor cells and slow the growth of cancer. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining chemotherapy and interferon alfa with radiation therapy after surgery may kill any remaining tumor cells. PURPOSE: This phase II trial is studying how well giving cisplatin, fluorouracil, and interferon alfa together with radiation therapy works in treating patients who have undergone surgery for stage I, stage II, or stage III pancreatic cancer.