1. Department of Medical Oncology Sun Yat‐sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine Guangzhou Guangdong 510060 P. R. China
2. Department of Colorectal Surgery Sun Yat‐sen University Cancer Center State Key Laboratory of Oncology in South China Collaborative Innovation Center for Cancer Medicine Guangzhou 510060 P. R. China
3. Department of Gastrointestinal Medical Oncology Peking University Cancer Hospital Beijing 100142 P. R. China
4. Department of Medical Oncology Tongji University Shanghai East Hospital Shanghai 200120 P. R. China
5. Department of Surgical Oncology The Second Affiliated Hospital of Zhejiang University School of Medicine Hangzhou Zhejiang 310009 P. R. China