Trial Assessing Roux-en-Y Anastomosis of the Pancreatic Stump to Prevent Pancreatic Fistula Following Distal Pancreatectomy

Inclusion Criteria: 1. disease of pancreatic body and tail 2. PS (ECOG Performance Status Scale):0-1 3. Age: 20 years or older 4. distant metastases are not diagnosed preoperatively. Eligible for this clinical study when only distal pancreatectomy contributes to the favorable prognosis even if patients with pancreatic neuroendocrine cancer have the liver metastasis. 5. Adequate organ functions filled the following criteria within two weeks from enrollment: 1.White blood cell： \>3,500/mm3 or \<12,000/mm3 2.Neutrophilic leukocyte \>2,000/mm3 3.Platelet\>100,000/mm3 4.Hemoglobin \> 9.0g/dL 5.Total bilirubin \<2.0mg/dL 6.AST and ALT\<150IU/L 7.Creatinine \<1.5mg/dL 6)Patients who can provide written informed consent Exclusion Criteria: 1. Patients with severe liver cirrhosis or active hepatitis 2. Patients with respiratory illness that requires oxygen administration 3. .Patients with chronic renal failure requiring dialysis 4. Patients with active duplicative malignant disease affecting adverse event 5. Others, patients who are unfit for the study as determined by the attending physician