1. Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
2. Department of Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Surgery, Cheil General Hospital and Women's Healthcare Center, Dankook University College of Medicine, Seoul, Korea.
5. Department of Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.