Multicenter phase I/II trial of adjuvant combination chemotherapy with gemcitabine and S-1 for pancreatic cancer

INTERVENTION: S1: bid d1‐7 q2w x 12 courses PO GEM: d1 q2w x 12 courses DIV The doses of GEM and S‐1 in the phase II trial are determined based on the results of the phase I trial. CONDITION: pancreatic cancer PRIMARY OUTCOME: Phase I: the maximum‐tolerated dose and dose‐limiting toxicity of GS therapy.; Phase II: overall survival. SECONDARY OUTCOME: Phase II: adverse events and disease‐free survival. INCLUSION CRITERIA: 1)Histologically proven pancreatic adenocarcinoma 2)Gross complete resection (R0 or R1) 3)No prior chemotherapy or radiotherapy 4)Age between 20 and 79 years 5)ECOG performance status of 0 or 1 6)Adequate hematologic, hepatic and renal function 7)Written informed consent