Postoperative Circulating Tumor DNA Monitoring in Stage I-III Driver-Mutant Colon Adenocarcinoma

This multicenter prospective observational cohort study will enroll 392 patients with stage I-III colon adenocarcinoma who undergo curative resection and whose tumors harbor at least one prespecified oncogenic driver mutation (KRAS, NRAS, BRAF, or PIK3CA). Serial plasma circulating tumor DNA (ctDNA) testing for molecular residual disease (MRD) will be performed with a standardized 10-gene next-generation sequencing (NGS) panel at predefined time points during 3 years of postoperative follow-up. The primary objective is to evaluate the association between postoperative ctDNA-based MRD status and recurrence-free survival (RFS). Secondary objectives include evaluating overall survival (OS), the interval between first MRD detection and radiologically confirmed recurrence, and the association between longitudinal MRD changes and outcomes following adjuvant chemotherapy.