1. Department of Oncology, Dezhou People's Hospital, Dezhou, Shandong�253014, P.R. China
2. Department of Proctology, Dezhou People's Hospital, Dezhou, Shandong 253014, P.R. China
3. Department of Gastrointestinal Surgery, Dezhou People's Hospital, Dezhou, Shandong 253014, P.R. China