Cetuximab, Radiotherapy and Twice Weekly Gemcitabine to Treat Pancreatic Cancer

Inclusion Criteria: * Histologic proof of pancreatic adenocarcinoma * Clinical stage I, II, or III disease * Radiographically measurable disease * Tumor tissue for epidermal growth factor receptor (EGFR) status by immunohistochemistry * Signed protocol consent * Karnofsky performance status of at least 70% * Age \> or = to 18 years * Patients must either not be of child bearing potential or have a negative pregnancy test within 72 hours of treatment. * Absolute neutrophil count (ANC) \> 1500; platelets \> 100,000/ul. * Creatinine \< 1.5 x upper limit of normal (ULN) * Bilirubin \< 1.5 x ULN; AST \< 2.5 x ULN. Exclusion Criteria: * Acute hepatitis or known HIV * Active or uncontrolled infection * Significant history of cardiac disease * Prior therapy which affects or targets the EGF pathway * Prior severe infusion reaction to a monoclonal antibody * Any concurrent chemotherapy not indicated in the study protocol or any other investigational agents * Any previous chemotherapy or abdominal or pelvic radiotherapy * No prior malignancy is allowed except for adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, or malignancy for which the patient has been disease free for five years. * Any severe pre-existing medical or psychiatric condition, which, in the opinion of the attending physician, will interfere with safe and appropriate treatment and follow-up on study