A Randomized Controlled Trial of Plasma ctDNA Methylation-Guided Adjuvant Chemotherapy Decision-Making in High-Risk Stage III (T4N+ or T1-3N2) Colorectal Cancer

Patients with T4N+ or T1-3N2 disease will be randomly assigned to either the control group (FOLFOX/CAPOX for 6 months) or the intervention group (FOLFOX/CAPOX plus bevacizumab for 6 months) to receive adjuvant therapy. Venous blood samples (8-16 mL) will be collected at 1 month, 3 months, and 6 months postoperatively for dynamic monitoring of plasma ctDNA.