Thermal Ablation for Autonomously Functioning Thyroid Nodules: A Prospective Comparison of Radiofrequency and Microwave Ablation.

OBJECTIVE

Thermal ablation is a minimally invasive treatment for autonomously functioning thyroid nodules with lower risk of hypothyroidism than surgery or radioactive iodine ablation, but data directly comparing thermal ablation modalities are limited. We compared radiofrequency ablation (RFA) and microwave ablation (MWA).

METHODS

In a prospective single-center cohort, 63 patients with toxic adenoma (TA) or toxic multinodular goiter (TMNG) underwent RFA (n = 47) or MWA (n = 16). The primary outcome was biochemical response, defined as normalization of serum thyroid-stimulating hormone. Secondary outcomes included volume reduction ratio (VRR), ablation time, and complications over 12 months.

RESULTS

Median baseline nodule volume was small (4.4 mL), a factor associated with more favorable biochemical response. Biochemical cure was achieved in 89% of patients overall, similar between modalities (P = .63). Contrary to prior reports, TMNG had higher cure rates than TA (100% vs 76%; P = .01). Median VRR exceeded 84% in both groups. MWA required significantly less time per milliliter than RFA (P = .01). Complication rates did not differ between modalities. Nodule rupture exceeded rates in the nonfunctioning nodule literature, possibly reflecting the greater energy required.

CONCLUSION

Thermal ablation is an effective treatment for autonomously functioning nodules, with RFA and MWA as complementary options. TMNG responded more favorably than TA, likely reflecting smaller nodule size. The greater energy required for toxic nodules may increase rupture risk. Trials with longer follow-up are needed to confirm durability and refine energy delivery.