1. Department of General Surgery, Osan Hankook Hospital, Osan, Korea.
2. Center for Liver and Pancreatobiliary Cancer, National Cancer Center, Goyang, Korea.
3. Biomedical Statistics Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea.
4. Center for Gastric Cancer, National Cancer Center, Goyang, Korea.
5. Department of Surgery, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Korea.