[Value of Ultrasound-guided Core-needle Biopsy for Evaluating the Performance of Radiofrequency Ablation for Low-risk Papillary Thyroid Microcarcinoma].

Objective To investigate the clinical value of core-needle biopsy(CNB)for low-risk papillary thyroid microcarcinoma(PTMC)after radiofrequency ablation(RFA). Methods A total of 190 patients(including 142 females and 48 males,20-74 years old)with unifocal low-risk PTMCs[mean volume of(106.29±96.15)mm]treated by RFA from June 2016 to September 2018 were evaluated in this study.During the RFA procedure,enlarged ablation was performed.Patients were followed up 1,3,6,12 months after RFA and every 6 months thereafter.The volume of ablation area and the volume reduction ratio(VRR)were calculated.To evaluate the ablation performance,CNB was performed to the central zone,the peripheral zone,and surrounding thyroid parenchyma 3 or 6 months after RFA. Results The mean follow-up time was(30.04±12.41)months.The mean volume of tumor significantly decreased from(106.29±96.15)mm to(1.47±8.00)mm.Two ablated tumors were diagnosed to have residue by CNB and underwent additional RFA.No recurrence,metastatic lymph nodes,or distal metastasis were found during the follow-up.All the patients were tolerable to RFA and CNB procedure. Conclusion CNB can be used to evaluate the ablation performance after RFA for low-risk PTMC.