Title Search [BP OP 3-1] EVALUATION OF CIRCULATING TUMOR DNA IN PORTAL VEIN BLOOD AS A BIOMARKER FOR EARLY RECURRENCE OF PANCREATIC CANCER Lingdi YIN (The First Affiliated Hospital of Nanjing Medical University, China) [BP OP 3-2] SIGNIFICANCE OF CONVERSION SURGERY FOR UNRESECTABLE BILIARY TRACT CANCER Ryusei MATSUYAMA (Yokohama City University, Japan) [BP OP 3-3] THE EFFECT OF PREOPERATIVE RADIOTHERAPY IN THE RESECTABLE PANCREATIC CANCER : A PROSPECTIVE SINGLE CENTER PILOT STUDY Seung Soo HONG (Severance Hospital, Yonsei University, Korea) [BP OP 3-4] PROPOSAL OF A NOVEL NODAL STAGING SYSTEM FOR RESECTED PANCREATIC CANCER AFTER NEOADJUVANT THERAPY Aram SHIN (Asan Medical Center, University of Ulsan, Korea) [BP OP 3-5] REVISITING THE SURGICAL STRATEGY OF T1B GALLBLADDER CANCER: A KOREA TUMOR REGISTRY SYSTEM BILIARY PANCREAS (KOTUS-BP) DATABASE ANALYSIS Hee Ju SOHN (Chung-Ang University Hospital, Korea) [BP OP 3-6] ROLE OF ADJUVANT CHEMOTHERAPY AFTER HEPATIC RESECTION FOR PATIENTS WITH INVASIVE INTRADUCTAL PAPILLARY NEOPLASM OF THE BILE DUCT (IPNB) Pun PUGKHEM (Faculty of Medicine, Khon Kaen University, Thailand) [BP OP 3-7] NEW PATHOLOGICAL RESPONSE SYSTEM; SHRINKAGE PATTERNS FOR RESECTABLE/ BORDERLINE RESECTABLE PANCREATIC CANCERS. Hidetaka MIYAZAKI (Kansai Medical University, Japan) [BP OP 3-8] OPTIMAL TREATMENT STRATEGY IN PATIENTS WITH SUBOPTIMAL RESPONSE WHO UNDERWENT INDUCTION CHEMOTHERAPY FOR LOCALLY ADVANCED PANCREATIC CANCER (LAPC): TO RESECT OR CONTINUE CHEMOTHERAPY? HYE-SOL JUNG (Seoul National University Hospital, Korea)