1. Department of Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
2. Department of Surgery, Ewha Womans University Mokdong Hospital, Seoul, Korea.
3. Cancer Research Institute, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
4. Department of Surgery, Gyeongsang National University Hospital, Changwon, Korea.
5. Department of Surgery, Gyeongsang National University Hospital, Jinju, Korea.
6. Department of Surgery, Keimyung University Dongsan Hospital, Daegu, Korea.