The study was conducted on patients with advanced right-sided colon cancer, and the clinical pathological and prognostic data of the patients were compared between the two groups of patients who were randomly divided into those undergoing SMV and SMA left resection, with the aim of resolving the controversy over the left resection boundary of CME/D3 lymph node dissection through this study, and to clarify whether SMA left resection is superior to SMV left resection.

Inclusion Criteria:

• right side colon cancer(The primary lesion is located in the ileocecal region, ascending colon, hepatic flexure of colon, or proximal transverse colon)
• T3-4 and/or N1-2M0
• Colonoscopy and pathological biopsy confirmed colon adenocarcinoma

Exclusion Criteria:

• T1-2N0M0
• Cannot undergo curative resection
• Simultaneous multiple primary colorectal cancer or other diseases requiring segmental resection
• Distant metastasis
• Tumor invades surrounding organs, requiring joint organ resection
• Emergency surgery is required for complications such as intestinal obstruction, perforation, and bleeding
• Patients who have received neoadjuvant therapy before surgery
• Pregnant or lactating women
• Patients who are not suitable or unable to tolerate surgery