Early Results of Radiofrequency Ablation for Treating Molecular Negative Bethesda III Thyroid Nodules

Radiofrequency ablation (RFA) has become an alternative option for management of symptomatic, large, or toxic benign (BII) thyroid nodules, but its role in treatment of thyroid nodules with Bethesda III (BIII) cytology is less described and controversial.

This was a retrospective review of a prospectively maintained database of all thyroid RFA patients at a single institution. Patients were eligible for RFA if they had a symptomatic, large, or toxic thyroid nodule with benign cytology on 2 separate biopsies, including BIII cytology with negative molecular profiling. Volume reduction ratio (VRR) and symptom improvement at 1, 6, 12, and 24 months were compared between BII and BIII nodules.

Of 174 thyroid RFA patients, 32 patients had 1 or 2 BIII biopsies. Most patients were female (86.8%) with an average age of 58.6 years and a mean follow-up of 8.2 months (median 6, range 1-31). Both BII and BIII nodules were most frequently solid (BII 52.1%, BIII 78.1%) or predominantly solid (BII 43.7%, BIII 18.8%; p > 0.05). The average maximum nodule diameter was similar between groups (BII 4.1 cm, BIII 4.0 cm, p > 0.05), as well as initial nodule volume (BII 20.2 cc, BIII 15.8 cc, p = NS). At 1-, 6-, 12-, 18-, and 24-month follow-up, there was a mean VRR of 45.3%, 64.8%, 74.8%, 75.5%, and 77.8% for BII nodules vs 46.4%, 69.0%, 81.6%, 72.3%, and 77.0% for BIII nodules (all p > 0.05). All patients with at least 6 months of follow-up had symptom improvement.

In our single institution study of RFA for patients with molecular negative BIII thyroid nodules, VRRs for BII and BIII nodules were similar at 12 months. RFA appears safe and effective for BIII nodules devoid of molecular alterations, though longer-term follow-up is needed.