This phase II study is designed to investigate the efficacy of intraoperative radiotherapy after neoadjuvant chemotherapy in patients with resectable pancreatic cancer. The purpose of the study is to show the local recurrence rate after neoadjuvant chemotherapy and IORT is superior to that of surgical resection alone from the historical control. A total of 80 patients will be enrolled, and these patients will receive IORT of 10 Gy at 5 millimeter depth of the tumor bed, following neoadjuvant chemotherapy.

Inclusion Criteria:

• Histologically diagnosed with adenocarcinoma of the pancreas or clinically diagnosed with imaging examinations or tumor markers
• 20 years or older
• Performance status 0-2 based on Eastern Cooperative Oncology Group (ECOG)
• Patients with surgically resectable or borderline resectable and advanced pancreatic cancer that can be resected after neoadjuvant chemotherapy
• Patients who voluntarily decided to participate in this clinical study and signed a written informed consent

Exclusion Criteria:

• History of previous abdominal irradiation.
• When the treatment area is not included in the appropriate radiation field according to the judgment of the radiation oncologist or Durgeon
• Distant metastasis
• Other systemic conditions that, under the judgment of the attending physician, would be difficult to undergo surgery or radiiotherapy