Radiofrequency Ablation for Solitary Autonomously Functioning Thyroid Nodules: Multicenter Study from Latin America

Background: Autonomously functioning thyroid nodules (AFTNs) represent ∼5% of all thyroid nodules and often necessitate definitive treatments such as surgery or radioiodine (¹³¹I), both of which have inherent risks. Radiofrequency ablation (RFA) has emerged as an effective and safe therapeutic option for managing AFTNs. This study aims to assess the effectiveness and safety of RFA for solitary AFTNs in various countries across Latin America. Methods: This retrospective, observational, multicenter cohort study included patients with a solitary AFTN that was histologically confirmed as benign and treated with a single session of RFA. The study included an analysis of patient demographics, sonographic characteristics of the nodules, thyroid profile assessment at each follow-up visit, evaluation of clinical symptoms to determine the achievement of a euthyroid state, and the measurement of nodule volume reduction. In addition, a bivariate analysis was conducted to identify associations between these variables and the resolution of hyperthyroidism. Results: Our study enrolled 81 patients with a solitary, benign AFTN. The volume reduction ratio (VRR) consistently increased over the follow-up period, with medians of -50%, -74.9%, -78.4%, and -90.2% at 1, 3, 6, and 12 months, respectively. The rate of resolution of hyperthyroidism was 93.8% (76/81). Following the RFA procedure, 58.02% of patients (47/81) normalized their thyrotropin levels within 1 month of follow-up, and by 3 months, an additional 33.3% had achieved normalization (27/81). Notably, a baseline volume ≥10, 20, or 30 mL did not affect the achievement of clinical success. In bivariate analyses, a VRR ≥50% at the 6-month follow-up was associated with the resolution of hyperthyroidism. Overall complications occurred in 6.2% of patients (5/81), including 1.2% (1/81) of a major complication (transient Horner syndrome), 3.7% cases of transient dysphonia (3/81), and 1.2% (1/81) of hypothyroidism requiring low-dose levothyroxine replacement. Conclusions: The results of this multicenter study suggest that RFA is a promising treatment option for patients with solitary AFTN, regardless of their baseline characteristics, including volume, age, or composition. The clinical success of the intervention may be related to the VRR at 6 months.