1. Patients initially diagnosed with primary colorectal cancer were enrolled for screening, and plasma samples 1-2 days before radical bowel resection were collected for polygene methylation detection.
2. The postoperative follow-up was 2 years, and the reexamination included CT/MRI imaging assessment, blood CEA, and dynamic monitoring of plasma ctDNA methylation level. Blood samples were collected for 9 times.
3. Results analysis: To explore the application value of ctDNA methylation-MRD detection in the prediction of postoperative tumor recurrence risk after radical resection of colorectal cancer; The correlation between preoperative ctDNA methylation level and prognosis of early colorectal cancer.