This phase II study is designed to investigate the efficacy of IORT for patients with resectable pancreatic adenocarcinoma. The purpose of the study is to show the local recurrence rate after surgical resection and IORT is superior to that of surgical resection alone from the historical control. A total of 42 patients will be enrolled, and these patients will receive IORT of 10 Gy at 5 millimeter depth of the tumor bed, followed by 6 cycles of adjuvant gemcitabine chemotherapy.

Treatment outcomes of pancreatic cancer are poor even after surgical resection, thus patients may receive adjuvant chemotherapy or chemoradiotherapy. Intraoperative radiotherapy (IORT) with low energy (50 kV) x-ray allows delivery of a high dose radiation to the tumor bed during surgery while effectively sparing adjacent critical organs. Another advantage of IORT is that delivery of IORT does not interfere with the scheduled administration of adjuvant chemotherapy or chemoradiotherapy. Here we investigate the efficacy of IORT for patients with resectable pancreatic adenocarcinoma by comparing the local recurrence rate after surical resection and IORT with that of surgical resection alone from the historical control. A total of 42 patients will be enrolled in this phase II trial, and these patients will receive IORT of 10 Gy at 5 millimeter depth of the tumor bed, followed by 6 cycles of adjuvant gemcitabine chemotherapy.

Inclusion Criteria:

• 1. Pathologically confirmed pancreatic adenocarcinoma 2. Age ≥20 years 3. Performance status ECOG 0-2 4. Patients must have resectable disease. In order to be resectable the following criteria must be met:
• Absence of distant metastases
• Clear fat planes around the celiac axis, hepatic artery, and superior mesenteric artery
• Absence of direct involvement of inferior vena cava or aorta
• Stage I-III disease per AJCC 7th edition 5. Laboratory data obtained ≤14 days prior to registration on study, with adequate bone marrow and renal function defined as follows:
• Hemoglobin >10 g/dL, Absolute Neutrophil Count (ANC) >1,500/mm3, Platelets >100,000/mm3
• Serum Cr <1.4 mg/dL, BUN <20 mg/dL 6. Ability to understand and the willingness to sign a written informed consent

Exclusion Criteria:

• 1. Patients who have received external beam radiotherapy in the abdominal area 2. Defined treatment area which cannot be adequately covered by the radiation field as defined by the radiation oncology treatment team 3. Patients who have received neoadjuvant chemotherapy 4. Stage IV disease 5. Patients with distant metastases 6. Current pregnancy or currently nursing