1. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P. R. China
2. Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangzhou, Guangdong, P. R. China
3. Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P. R. China
4. Department of General Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, P. R. China
5. Endoscopy Center, Zhongshan Hospital, Fudan Univeristy, Shanghai, P. R. China
6. Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China
7. Department of Gastrointestinal Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, P. R. China
8. Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Diseases, Beijing, P. R. China
9. Department of Gastrointestinal Cancer Center, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, P. R. China