Neoadjuvant S-1 and Concurrent Radiotherapy for Borderline Resectable Pancreatic Cancer

S-1: S-1 is an oral fluorinated pyrimidine agent which contains tegafur (FT, a prodrug of 5-FU), 5-chloro-2,4-dihydropyrimidine (CHDP) and potassium oxonate (Oxo) effective for gastric and various other types of cancers. S-1 is also active for pancreatic cancer: S-1 demonstrated non-inferiority to gemcitabine in overall survival for metastatic or locally advanced pancreatic cancer (LAPC). S-1 and Concurrent radiotherapy: S-1 therapy with concurrent radiation therapy (RT) had favorable activity with overall tumor response rate of 37%, as well as mild toxicity in patients with LAPC. The median survival time and the 2-year survival rate for LAPC patients treated by S-1/RT were 16.2 months and 26% respectively. Definition of Borderline Resectable Pancreatic Cancer:(1) Reconstructible bilateral impingement of superior mesenteric vein or portal vein; (2) Tumor contact with the superior mesenteric artery (SMA) of \</= 180 degrees ; (3) Tumor contact with the common hepatic artery of \</= 180 degrees (at the root of the gastroduodenal artery); and (4) Tumor contact with the celiac axis of \</= 180 degrees. Tumor with portal vein tumor thrombus and tumor contact with the second or further jejunal SMA branch are considered as unresectable. Tumor which is contact with the common hepatic artery or celiac axis but can be resected by distal pancreatectomy with en bloc celiac axis resection, is not included in this study.