Treatment outcomes in patients with papillary thyroid cancer undergoing radiofrequency ablation of metastatic lymph nodes.

Background: Lymph node metastases in papillary thyroid cancer (PTC) increases recurrence risk and negatively impact survival. Traditional treatments like re-operation and radioactive iodine (RAI) have downsides. Radiofrequency ablation (RFA) is an emerging non-surgical therapeutic option, but there is seldom data on its efficacy and safety specifically for metastatic lymph nodes. We aimed to evaluate clinical outcomes of RFA applied to cervical lymph nodes in patients with PTC metastasis in North American population.

Methods: This was a single-institution retrospective analysis of 68 PTC patients with lymph nodes who underwent percutaneous RFA from January 2020 to December 2022. Volume reduction ratio (VRR), changes in thyroglobulin (Tg) levels, lymph node regrowth rate, and complications were assessed. Treatment response and outcomes were analyzed.

Results: Median lymph node maximum diameter was 12.9 mm and median volume was 0.27 mL at baseline. After RFA, median VRR was 79.5% [interquartile range (IQR), 50-89.7%]. Post-RFA, Tg to an average of 0.2 ng/mL (IQR, 0-0.6 ng/mL). In the 19 patients (27.9%) with undetectable Tg after RFA, median VRR was 86% (IQR, 73-94%). Quantitative Tg decrease strongly correlated with VRR percentage (r=0.82, P<0.001). Lymph node regrowth was seen in 5 patients (7.4%) over median 18 months follow-up. Only one patient experienced transient thermal injury associated with Horner's syndrome and symptoms resolved within 1 month.

Conclusions: In patients with PTC and metastatic cervical lymph nodes, RFA provided marked volume reduction and meaningful biochemical response without major complications. Excellent radiographic control was achieved in most patients. RFA demonstrates early promise as an emerging non-surgical therapeutic option for PTC patients with metastatic lymph nodes.