1. Center for Liver and Pancreatobiliary Cancer, National Cancer Center, Goyang, Korea.
2. Korea Central Cancer Registry, National Cancer Center, Goyang, Korea.
3. Division of Cancer Registration and Surveillance, National Cancer Control Institute, National Cancer Center, Goyang, Korea.
4. Department of Surgery, Chung-Ang University Gwang-Myeong Hospital, Gwangmyeong, Korea.