1. Department of Gastroenterology, The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu 223002, P.R. China
2. Department of Gastroenterology, The First People's Hospital of Lianyungang, Xuzhou Medical University Affiliated Hospital of Lianyungang, Lianyungang, Jiangsu 222002, P.R. China
3. Department of Radiotherapy, The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu 223002, P.R. China
4. Medical Center for Digestive Diseases, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, P.R. China