This study aims to evaluate the use of node-sparing short-course radiotherapy combined with chemotherapy and Sintilimab, or chemotherapy alone, as neoadjuvant therapy for MSS-type locally advanced colon cancer. The goal is to explore the efficacy and safety of combining node-sparing short-course radiotherapy with chemotherapy and immunotherapy in the neoadjuvant setting for MSS-type locally advanced colon cancer, while also investigating the specific role of regional lymph nodes in tumor immunotherapy.
1. Patients willing to undergo neoadjuvant treatment. 2. Age ≥ 18 years. 3. Tumor confirmed by colonoscopy and enhanced abdominal CT to be ≥ 12 cm from the anal verge.
White blood cell count ≥ 3.5 × 10^9/L, absolute neutrophil count ≥ 1.5 × 10^9/L, platelet count ≥ 100 × 10^9/L, hemoglobin concentration ≥ 9 g/dL;
Liver function tests (bilirubin ≤ 1.5 × ULN; AST and ALT ≤ 5 × ULN);
Renal function (serum creatinine ≤ 1.5 × ULN or creatinine clearance (CCr) ≥ 50 mL/min);
1. History of other malignancies within the past 5 years. 2. Patients with metastases in other locations (stage IV). 3. Patients with MSI-H or dMMR. 4. Patients with conditions such as bowel obstruction, perforation, or bleeding requiring emergency surgery.