1. Department of General Surgery, The 6th Affiliated Hospital of Kunming Medical University, The People's Hospital of Yuxi City, Yuxi, Yunnan 653100, P.R. China
2. Department of Gastrointestinal Surgery, Liaocheng People's Hospital Affiliated to Shandong University and Clinical School of Taishan Medical University, Liaocheng, Shandong 271099, P.R. China
3. Department of Health Screening Center, The 6th Affiliated Hospital of Kunming Medical University, The People's Hospital of Yuxi City, Yuxi, Yunnan 653100, P.R. China
4. Department of Colorectal Surgery, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, P.R. China
5. Department of General Practice, The 6th Affiliated Hospital of Kunming Medical University, The People's Hospital of Yuxi City, Yuxi, Yunnan 653100, P.R. China