Objective To assess the local treatment efficacy of percutaneous radiofrequency ablation(PRFA) in combination with percutaneous ethanol injection(PEI) therapy protocol for liver metastases in patients with colorectal cancer.Methods From February 2000 to February 2004, total of 61 liver metastatic lesions(1.5～7.8 cm) from 37 colorectal cancer patients were ablated by using RF-2000 generator and 10-needle LeVeen electrode percutaneously guided by B-ultrasound.Tumors larger than 2.5 cm in diameter were treated by multiple overlapping radiofrequency ablations encompassing the entire lesion as well as a rim of normal liver tissue(approximately 1.0 cm).PEI was performed additionally.The Chiba needle and Quadra-Fuse multi-pronged injection needle were used for tumors ranged 1～2 cm and for those larger than 3 cm respectively.Results The procedures were performed successfully in all patients.The post-PRFA/PEI complication rate was 5.4%.The follow-up rate was 97.3%(36/37).Thirteen patients achieved a complete response(CR),and 21 achieved a partial response(PR).The effective rate(CR+PR) was 94.4%.The patients' survival rates were 97.2% at 1 year,75.0% at 2 years,and 52.8% at 3 years respectively.Conclusion The results of this study suggest that the treatment protocol of PRFA in combination with PEI was an effective mini-invasive local ablation therapy,which was part of the comprehensive management of the colorectal liver metastases.