Vaccine Therapy With or Without Cyclophosphamide in Treating Patients Undergoing Chemotherapy and Radiation Therapy for Stage I or Stage II Pancreatic Cancer That Can Be Removed by Surgery

DISEASE CHARACTERISTICS: * Newly diagnosed adenocarcinoma of the head, neck, or uncinate process of the pancreas * Stage I or II disease * Surgically resectable disease (R0 or R1) by spiral CT scan * No distant metastases * A clear fat plane is present around the celiac and superior mesenteric arteries * Patent superior mesenteric and portal veins * Candidate for a pancreaticoduodenectomy PATIENT CHARACTERISTICS: * ECOG performance status 0-1 * Hemoglobin ≥ 9 g/dL * ANC ≥ 1,500/mm³ * Platelet count ≥ 100,000/mm³ * Serum creatinine ≤ 2 mg/dL * AST and ALT ≤ 2 times upper limit of normal (ULN) * Amylase ≤ 2 times ULN * Alkaline phosphatase ≤ 5 times ULN * Hyperbilirubinemia secondary to tumor-associated extrahepatic biliary obstruction allowed * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for ≥ 4 weeks after the completion of study treatment * No history of autoimmune disease, including systemic lupus erythematosus, sarcoidosis, rheumatoid arthritis, glomerulonephritis, or vasculitis * No uncontrolled medical problems * No active infections * No other cancer within the past 5 years except for superficial bladder cancer, nonmelanoma skin cancer, or low-grade prostate cancer not requiring therapy PRIOR CONCURRENT THERAPY: * More than 28 days since prior anticancer therapy * No prior cancer immunotherapy, including the same pancreatic cancer vaccine used in this study * More than 28 days since prio…