1. Shantou University of Medical College, Shantou 515000, China
2. Department of General Surgery, Guangdong Provincial People’s Hospital, School of Medicine, South China University of Technology, Guangzhou 510080, China
3. Forth Department of Geriatrics, General Hospital of Southern Theater Command, PLA, Guangzhou 510080, China
4. Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
5. Guangzhou Medical University, Guangzhou 511436, China
6. Department of Hepatobiliary Surgery, The Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China