Comparison Between Pylorus-resecting and Preserving Pancreaticoduodenectomy on Delayed Gastric Emptying and Nutrition

Inclusion Criteria: * Age: 18 to 79 years * Performance: Eastern Cooperative Oncology Group (ECOG) 0-2 * The preoperative examination showed that the lesion could invade to major artery. * No distant metastasis * Bone marrow function: white blood cell (WBC) at least 3,000 / mm3, Platelet count at least 100,000 / mm3 * Liver function : aspartate transaminase (AST)/alanine transaminase(ALT) less than 3 times upper limit of normal * Kidney function: Creatinine no greater than 1.5 times upper limit of normal. * Patients who consented to and signed the consent Exclusion Criteria: * Patients diagnosed with duodenal cancer * Those with active or uncontrolled infections * Those with severe psychiatric / neurological disorders * Alcohol or other drug addicts * Patients who underwent previous major abdominal surgery (ex. gastrectomy, colectomy) * Patients included in other clinical studies that may affect this study * Patients who cannot follow the directions of the researcher * Those with uncontrolled heart disease * Patients with moderate or severe comorbidities who are thought to have an impact on quality of life or nutritional status (ex. cirrhosis, chronic kidney failure, heart failure, etc.) * Pelvic tumor, benign tumor, malignant tumor in other organs * Patients who received prior chemotherapy * In addition to the planned pancreaticoduodenectomy, patients who require resection of other major abdominal organs, such as gastrectomy, colectomy