1. Department of Gastric Surgery; Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine; 651 Dongfeng East Road Guangzhou 510060 Guangdong P. R. China
2. Department of Surgical Oncology; The First Affiliated Hospital of China Medical University; Shenyang 110000 Liaoning P. R. China
3. Department of Gastric Cancer Surgery; Tianjin Medical University Cancer Hospital; Tianjin 300000 P. R. China
4. Department of General Surgery, Nanfang Hospital; Southern Medical University; Guangzhou 510515 Guangdong P. R. China
5. Department of Gastroenterology Surgery; Guangdong General Hospital; Guangzhou 510030 Guangdong P. R. China
6. Department of Preventive Medicine, School of Public Health; Sun Yat-sen University; Guangzhou 510275 Guangdong P. R. China