1. Department of Gastroenterology, The First Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
2. Sun Yat‑sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China
3. Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510655, P.R. China