Evaluation of the efficacy of microwave ablation therapy for benign thyroid nodules of different compositions

To evaluate the 2-year nodule volume reduction rate (VRR), recurrence rate, and safety of ultrasound-guided microwave ablation (MWA) for benign thyroid nodules with different compositions, and to identify independent risk factors affecting therapeutic outcomes.

A single-center retrospective cohort study was conducted on 508 benign thyroid nodules (from 462 patients) treated with MWA between January 2018 and December 2023. Nodules were categorized as solid (G1), predominantly solid (G2), or predominantly cystic (G3). VRR, recurrence, and complications were assessed at 1, 3, 6, 12, and 24 months post-ablation. Multivariate regression and Kruskal-Wallis tests were used for statistical analysis.

A significant interaction between follow-up duration and nodule composition was observed for VRR (p < 0.001). At 24 months, the overall median VRR was 86.02%, with G3 (92.46%) significantly higher than G1 (84.32%) and G2 (85.55%) (p < 0.001). The 2-year recurrence rate was 2.56% (G1: 3.35%, G3: 0%), and the overall complication rate was 7.48% (G1: 14.50% > G3: 6.36%, p = 0.028). Multivariate analysis identified nodule composition as an independent predictor of VRR (β = 0.783, p < 0.001) and recurrence (OR = 4.21, p = 0.005), while a maximum nodule diameter >60 mm was a recurrence risk factor (OR = 3.87, p = 0.020). Higher ablation parameters in G1 correlated with increased complications (p < 0.05).

Ultrasound-guided MWA is effective and safe for benign thyroid nodules, with cyst-dominant nodules demonstrating the best prognosis. Nodule composition is a core determinant of efficacy and recurrence, and higher ablation parameters are associated with increased complication risks.