Ablative Carbon Ion Radiotherapy With Pencil Beam Scanning for Locally Advanced Unresectable Pancreatic Cancer

The aim of this study is to investigate the clinical efficacy and safety of ablative carbon ion radiotherapy for locally advanced unresectable pancreatic cancer using pencil beam scanning and simultaneous integrated boost technology with respect to toxicity and tumor control. All enrolled patients will receive carbon ion radiotherapy for the primary pancreatic lesions, positive lymph nodes, and retroperitoneal high-risk recurrence areas. The prescription dose for primary pancreatic lesion, positive lymph node, and retroperitoneal high-risk recurrence area is 67.5 Gy (RBE weighted dose) in 15 fractions for 3 weeks; Pancreatic primary lesion and positive lymph node SIB to 75 Gy (RBE weighted dose) in 15 fractions for 3 weeks. The primary endpoint is 2-year cumulative local regional progression rate (LRP), and the secondary endpoint is to assess the overall survival (OS) and toxicities. Toxicity was assessed using the Common Adverse Event Evaluation Criteria (CTCAE) Version 5.0, and safety and toxicity will be assessed by clinical examination, laboratory examination, and imaging (including CT, MRI, and/or PET/CT).