Korea University College of Medicine, Seoul, South Korea. Department of Surgery, Korea University College of Medicine, Seoul, South Korea. Department of Surgery, Gyeongsang National University College of Medicine, Jinju, South Korea. Department of Surgery, Pusan National University College of Medicine, Pusan, South Korea. Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, South Korea. Department of Surgery, Dongnam Institute of Radiological & Medical Science, Pusan, South Korea. Department of Surgery, Dankook University College of Medicine, Cheonan, South Korea. Department of Surgery, Chonnam National University College of Medicine, Gwangju, South Korea. Department of Surgery, Daegu Catholic University School of Medicine, Daegu, South Korea. Department of Surgery, Kyung Hee University College of Medicine, Seoul, South Korea. Department of Gastric Surgery, Shanghai Medical College of Fudan University, Shanghai, China. Department of Surgery, Korea University College of Medicine, Seoul, South Korea. Electronic address: kugspss@korea.ac.kr.