Material and Method: With Institutional Review Board approval, we retrospectively reviewed RFA procedure between June 2006 and September 2013. Fifty-seven metastatic nodules in 36 patients were treated. The primary tumors were colorectal carcinoma (n = 30), neuroendocrine tumor (n = 2), gallbladder carcinoma (n = 1), adenocarcinoma of head of pancreas (n = 1), and gastrointestinal stromal tumor (n = 2). Tumor characteristics, RFA techniques, success rate, complication, and follow-up imaging were reviewed and recorded. Clinical outcome and overall survival were analyzed.

Results: Complete ablation were found in 48/57 nodules (84.2%). The mean follow-up time was 17.9±13.1 months (range, 1 to 47 months). Local tumor recurrence were noted in 12/57 nodules (21.1%), which mean time to recurrence was 8.3±3.8 months (2 to 15 months). Residual tumor was associate with tumor larger than 3 cm (p = 0.009). The 1-, 3-, and 5-year overall survival rates were 93.6%, 56.2%, and 20%, respectively. Median overall survival was 37.8±10.9 months. Major complication rate occurred about 5.3%.

Conclusion: Radiofrequency ablation is effective and feasible method to treat small metastatic liver tumor. Tumor size larger than 3 cm is significant risk factor of residual tumor. Tumor in high-risk location is not associated either incomplete ablation or local tumor recurrence.

Keywords: Radiofrequency ablation, Liver metastasis