Abstract: Objective The aims of this study were to improve the understanding of ultrasound-guided percutaneous microwave ablation for cervical lymph node metastasis after papillary thyroid carcinoma surgery,and to evaluate its efficacy and safety.Methods A study of 84 patients with postoperative recurrent papillary thyroid carcinoma was selected.After receiving microwave ablation,ultrasound contrast enhancement examination was performed to assess tumor activity in the ablation zone.The patient′s tumor size,volume,serum thyroglobulin and clinical evaluation were carried out in 1,3 and 6 months,and 12 months thereafter.Results A total of 103 patients with cervical lymph node metastases were successfully treated by microwave ablation.After treatment,ultrasound contrast enhancement examination did not detect incomplete ablation.During the last follow-up,the average maximum diameter decreased from 10.5±5.7mm to 0.8±1.5mm(P＜0.05),and the average volume was reduced from 285.9±245.7mm³ to 4.0±8.0mm³(P＜0.05).After the treatment,neither the progression of the treated tumor was detected nor the suspicious lymph nodes added.Conclusion Ultrasound-guided percutaneous microwave ablation may become an alternative therapy for thyroid papillary carcinoma patients with lymph node metastasis who are not suitable or refuse to undergo surgical treatment.This operation is safe and effective,and the incidence of complications is low.

Key words: Papillary thyroid carcinoma, Lymph node metastases, Microwave ablation