Background

Radiofrequency ablation (RFA) has emerged as a promising treatment option for autonomous functioning thyroid nodules (ATN). At present, ATN is preferentially treated with I-131, but this may lead to undesirable hypothyroidism. We aimed to assess the treatment efficacy of RFA in ATN and factors that may affect treatment success.

Methods

Retrospective analysis of patients with hyperthyroidism caused by ATN who were treated with RFA. Patients were included if follow-up of at least one year was available. Cure was defined as thyroid medication-free biochemical euthyroidism. Proportions were compared by the chi-squared test. Results of patients with a single toxic adenoma (STA) or toxic multinodular goitre (TMG) were compared.

Results

We included 48 patients (36 STA, 12 TMG), 85% were female, mean age was 55 years. Median nodule volume was 12 mL at baseline. One year after RFA, 29 patients (60.4%) were cured, median time to cure was 3.2 months. One patient, with a history of hemithyroidectomy, developed hypothyroidism.

The one-year cure rate was higher in STA than TMG patients: 72% versus 25% (p <0.05). Cured patients had significantly higher baseline TSH and energy delivered during RFA than non-cured patients.

Extended follow-up was available for 31 patients (median 20 months after first intervention). A second RFA treatment resulted in cure in 9 of 13 (69%) patients who remained hyperthyroid after the first RFA. After 1 or 2 RFA sessions cure was achieved in 86% of STA patients and in 33% of TMG patients at last available follow-up. Late recurrent hyperthyroidism was observed in 4 patients between 24-37 months after RFA.

Conclusion

The efficacy of single session RFA session was nearly 3 times higher in STA patients compared to TMG. These data confirm that RFA is an effective treatment for STA. Further analysis is required to assess the role of RFA in TMG. Long term follow-up after RFA should be considered as late recurrences are observed.