Abstract: Background and purpose: Since the number and tumor size of localized liver metastases can be controlled, local minimally invasive treatment can improve the survival of patients. Hence, microwave ablation has become an important treatment method for liver metastases. This study was to investigate the value of percutaneous microwave ablation in the treatment of tumor metastases. Methods: From Sep. 2011 to Oct. 2014, 26 advanced nasopharyngeal carcinoma patients with post-chemotherapy consolidation, liver metastases were collected. All the patients with the number of tumor lesions less than 3, diameter less than 5 cm, no other distant metastases was excluded. The ultrasound-guided percutaneous microwave ablation was used for 26 patients. Finally, 43 ablations were completed followed by liver function test, enhanced CT and MRI diagnosis 1 month later. mRECIST criteria was used to evaluate the efficacy of cancer treatment. Progression-free survival (PFS) and overall survival (OS) were calculated. Results: Twenty-six cases of a total of 53 lesions, including complete ablation (CA) 20 patients (20/26, 77.0%), partial ablation (PA) 3 patients (3/26,11.5%). The overall efficiency was 88.5% (CA + PA) with no serious complications. 6 months, 1-, 2-year survival rates of 26 patients were 96.1%, 65.3% and 23.0%. PFS was 11.4 months. The median survival time (MST) was 11.9 months, while OS was 23.7 months. Conclusion: Percutaneous microwave ablation for limited liver metastases of nasopharyngeal carcinoma is a minimally invasive, safe and effective treatment method.

Key words: Nasopharyngeal carcinoma, Microwave ablation, Liver metastases, B ultrasound guidance