Evaluation of Circulating Tumor DNA Guided Surveillance Strategy of Stage III Colorectal Cancer: an Open, Prospective, Randomized Controlled Cohort Study

For patients with stage III colon cancers, radical resection of primary tumor followed by adjuvant chemotherapy is currently the standard treatment. Adjuvant chemotherapy with 5-fluorouracil and oxaliplatin based regimen has been proved effective to improve recurrence-free survival and overall survival. Approximately half of patients with stage III colon cancers can be cured by surgery alone, while a substantial number of patients still experience recurrence, even with standard adjuvant chemotherapy. In recent years, circulating tumor DNA (ctDNA) has been detected in the cell-free component of peripheral blood samples in advanced colorectal cancers and many other solid tumors. Several previous studies have suggested that in patients with stage I-III colorectal cancer, postoperative ctDNA was an valuable biomarker to predict minimal residual disease (MRD) after radical resection, thus redefining patients risk outcome groups and guiding postoperative treatment. In addition, recent studies based on serial postoperative ctDNA detection showed that serial ctDNA analyses revealed disease recurrence up to 5-16.5 months ahead of radiological imaging. Here, based on the role of ctDNA in predicting MRD, we conducted an open, prospective, randomized controlled phase II cohort study to explore if ctDNA can as a biomarker to guide personalized surveillance strategy after surgery.