1. Department of Surgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea.
2. Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Surgery, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
4. Department of Surgery, National Cancer Center, Goyang, Korea.
5. Department of Surgery, Yeungnam University College of Medicine, Daegu, Korea.
6. Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
7. Department of Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.