1. Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
2. Cancer Research Institute, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China
3. Department of Pain Management, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China
4. Department of Anorectal Surgery, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China
5. Department of Gastroenterology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China