Dynamic ctDNA Detection for Colorectal Cancer Liver Metastases

Inclusion Criteria: 1. Before implementing any trial-related procedures, written informed consent should be signed; 2. \>=20 and \<= 85 years old, male or female; 3. Patients with liver metastases pathologically confirmed as colorectal adenocarcinoma; 4. According to the Response Evaluation Criteria for Solid Tumors (RECIST version 1.1), there is at least one lesion that can be measured by imaging; 5. The multidisciplinary team (MDT) confirmed that the liver metastases were initially resectable ,without locally treatable extrahepatic metastases; 6. The general physical condition is good (ECOG score 0-1); 7. Life expectancy of more than 3 months; 8. There is no obvious symptoms of primary bleeding, obstruction and other indications for emergency surgery; 9. adequate organ function; 10. samples meet NGS quality control requirements; 11. The subjects are able and willing to comply with the visits, treatment plans, laboratory tests and other research-related procedures stipulated in the research protocol. Exclusion Criteria: 1. Patients who are intolerant to systemic chemotherapy or surgery; 2. Patients with multiple primary lesions; 3. Blood samples and/or baseline tissue samples that do not meet the requirements for testing (hemolysis, low tumor cell content, insufficient DNA extraction yield, etc.); 4. Excessive tissue necrosis after conversion therapy, making it impossible to sample according to testing requirements 5. Patients who have not undergone surgery after conversion therapy, only receiving radiofrequency ablation or chemotherapy follow-up 6. Not all metastatic lesions were resected after conversion therapy, or liver metastatic lesions did not achieve R0 resection 7. No definite mutations detected in the tissue, or mutations detected in tumor tissue were not covered by the designed small panel.