Efficacy and Safety of Ultrasound-Guided Thermal Ablation for Locally Recurrent Cervical Lymph Node Metastasis After Thyroidectomy in Papillary Thyroid Carcinoma: A Multicenter Retrospective Study.

RATIONALE AND OBJECTIVES: Post-thyroidectomy recurrent cervical lymph node (LN) metastasis from papillary thyroid carcinoma (PTC) remains a clinical challenge and repeat surgery in a previously operated neck can be technically difficult and morbid. Ultrasound-guided thermal ablation (US-guided TA) has emerged as a minimally invasive treatment option, but contemporary multicenter real-world data with clearly defined short-term and longitudinal outcomes remain limited. This study evaluated the efficacy and safety of US-guided TA for treating locally recurrent cervical LN metastases from PTC in a multicenter cohort. MATERIALS AND METHODS: This retrospective multicenter study included 101 patients with 128 metastatic LNs treated at three tertiary centers between January 2018 and December 2025. Eligible lesions were confirmed by fine-needle aspiration biopsy cytology and/or washout thyroglobulin and were treated with radiofrequency ablation (RFA) or microwave ablation (MWA) because repeat surgery was considered unsuitable or was declined by the patient. All lesions had to be visible on real-time ultrasonography and technically accessible through a safe needle route. Follow-up was performed at 1 month, 3 months, 6 months, every 6 months until 2 years, and annually thereafter. Primary outcomes included technical success, technique efficacy at 1 month (complete ablation without residual enhancement on contrast-enhanced ultrasound), local tumor progression (LTP), and complication rates. Secondary outcomes were serum thyroglobulin (Tg) change and volume reduction ratio (VRR). Exploratory regression analyses were performed to assess factors associated with LTP. RESULTS: Technical success was achieved in 100% of treated LNs. The technique efficacy rate at 1 month was 97.65% (125/128 LNs). During a mean follow-up of 29.09± 8.05months (range, 6-48months), the LTP rate was 8.59% (11/128 LNs). Major complications occurred in 0.99% of patients (1/101), and minor complications occurred in 9.9% (10/101). Serum Tg levels decreased significantly from 13.02 ± 15.97 ng/mL before ablation to 0.12 ± 0.36ng/mL at the last follow-up (p < 0.001). The mean VRR at the last follow-up was 98.86%±5.93%. CONCLUSION: In this selected multicenter cohort, US-guided TA was associated with high technical success, favorable local control, marked lesion shrinkage, and low major-complication rate for locally recurrent cervical LN metastases from PTC. Because this was a retrospective single-arm study without a surgical or surveillance comparator, these findings should be regarded as exploratory real-world evidence supporting TA as a possible minimally invasive locoregional treatment option for carefully selected patients who are unsuitable for or decline repeat surgery, rather than establishing superiority to alternative management strategies.