CTC vs Radiography as the Evidence of Recurrence in Colorectal Cancer Patients

This study enrolled patients who underwent R0 resection of tumor and had elevated tumor biomarkers (CEA, CA19-9). After enroll the study, a CTC test will performed and patients who had positive CTC will be randomly assigned to two groups. The control group will continue follow-up until radiological recurrence appear, the treatment group will start treatment or change the current adjuvant regimen. First endpoint is OS. The secondary endpoint is DFS, adverse event.