Circulating tumor DNA to detect minimal residual disease, response to adjuvant therapy, and identify patients at high risk of recurrence in patients with stage I-III CRC.

4009 Background: The clinical utility of tracking circulating tumor DNA (ctDNA) as a non-invasive biomarker for detecting minimal residual disease (MRD) and stratifying patients based on their risk of developing relapse has been well established in colorectal cancer (CRC). This study evaluates the detection and longitudinal monitoring of ctDNA in CRC patients pre- and post-operatively, during and after adjuvant chemotherapy (ACT). Methods: The prospective, multicenter cohort study recruited patients (n = 193) diagnosed with resected stage I-III CRC. Plasma samples (n = 1052) were collected at various timepoints with a median follow up of 21.6 months (4.6-38.5 months). Individual tumors and…