Comparison of Hepatectomy and Local Ablation for Resectable Synchronous and Metachronous Colorectal Liver Metastasis

Inclusion Criteria: 1. At least one metastatic adenocarcinoma of liver, histologically proven. 2. At least one adenocarcinoma of colon and/or rectum, histologically proven. 3. No local complication at the time of surgery (no occlusion, no sub-occlusion, no massive hemorrhage, no abscesses or local invasion). 4. No extra-hepatic metastasis. 5. Extra-hepatic disease (EHD) suitable for hepatectomy, liver ablation and anesthesia as long as all sites of EHD disease are radically treated. 6. All the primary and secondary tumors which R0 resections are technically possible. (SCRLM: synchronous resection for both primary and secondary tumors, MCRLM: no local recurrence within 6 months after resection of primary tumor) 7. Residual hepatic volume\>30%-40%. 8. At least 2-3 hepatic segments remained after hepatectomy (except S1), residual liver with normal portal vein, hepatic artery and biliary duct, at least 1 of hepatic veins (left, middle and right) not invaded. 9. Tumor size ≤3 cm. 10. Tumor number≤ 3. 11. Tumors located ≥1.0 cm of vulnerable structures, e.g. colon, main trunk of portal vein, hepatic artery, hepatic vein and intrahepatic biliary duct. 12. suitable for both hepatectomy and local ablation after multiple disciplinary team(MDT) discussion. 13. Informed written consent. Exclusion Criteria: 1. Other malignant tumors history. 2. Complications need emergency surgery (occlusion, sub-occlusion, massive hemorrhage and abscesses, et al.). 3. Colorectal or hepatic tumor extension towards abdominal wall and/or adjacent organ making liver R0 resection impossible immediately. 4. Hepatic lesions diagnosed with ultrasound and MRI making complete ablation impossible immediately. 5. ≤ 2 hepatic segments remained after hepatectomy or residual hepatic volume﹤30%-40% 6. Non resectable lymph node metastasis. 7. American Society of Anesthesiologists(ASA) grading≥ IV and/or Eastern cooperative oncology group(ECOG) score≥ 2. (see appendix) 8. EHD is not recommended. 9. Physical or psychological dependence. 10. Pregnant or breast feeding women. 11. Not controlled preoperational infection. 12. Enrolled in other clinical trials within 4 weeks. Other clinical or laboratorial condition not recommended by investigators.