1. Scope This guideline specifies the standardized diagnosis and treatment process, diagnostic basis, diagnosis and differential diagnosis, treatment principles and treatment plan of colon cancer. This guideline applies to the diagnosis and treatment of colon cancer in designated hospitals of rural major diseases medical insurance work. 2 .Terms and definitions The following terms and definitions are applicable to this guideline. Hereditary nonpolyposis colorectal cancer (HNPCC): It is an autosomal dominant genetic syndrome, also known as lynch syndrome. 3, Abbreviations The following abbreviations apply to this guideline. CEA: (carcinoembryonic antigen) carcinoembryonic antigen.