Cytological Alterations of Benign Thyroid Nodules Following Radiofrequency Ablation.

Background: Radiofrequency ablation (RFA) has emerged as a minimally invasive treatment for benign thyroid nodules. However, concerns exist about potential cytological progression following RFA. This study investigated the incidence of progression from benign (Bethesda II) to indeterminate (Bethesda III-IV) cytology and evaluated RFA's long-term efficacy and safety.

Methods: This prospective study included patients with benign thyroid nodules treated with RFA from July 2019 to December 2023. Pre- and post-ablation fine-needle aspiration (FNA) cytology results were analyzed. Treatment efficacy was assessed through nodular volume changes and thyroid function, while safety was evaluated through complication rates.

Results: Among 312 benign thyroid nodules treated with RFA, post-ablation FNA showed 12 cases (3.84%) progressed to Bethesda III, all confirmed benign by Afirma Gene Sequencing Classifier. Three patients underwent surgical resection due to inadequate volume reduction, with histopathology confirming benign nature. RFA achieved sustained nodular volume reduction, with a median reduction rate of 88% at 60 months. The overall complication rate was 3.2%, with no major complications requiring hospitalization.

Conclusions: RFA demonstrates low risk of cytological progression and high efficacy in treating benign thyroid nodules. The significant volume reduction and favorable safety profile support RFA as a viable surgical alternative in selected patients. Future studies with larger cohorts and longer follow-up are needed to validate these findings and identify treatment success predictors.

Level of evidence: 3: