The Efficacy of Ultrasound-Guided Microwave Ablation for Benign Thyroid Nodules and the Correlation Analysis of Its Influencing Factors

Objective: To investigate the efficacy of ultrasound-guided microwave ablation (MWA) for benign thyroid nodules and to analyze the correlation between treatment outcomes and various influencing factors. Methods: 95 patients with pathologically confirmed benign thyroid nodules（ totally 96 nodules) who underwent MWA under ultrasound guidance were enrolled in this retrospective study. Pre-ablation and post-ablation follow-up examinations including two-dimensional ultrasound, color Doppler, and contrast-enhanced ultrasound were conducted at 1, 3, and 6 months. The clinical efficacy was assessed, including the reduction in nodule volume and the success rate of ablation. Factors that might influence treatment outcomes, such as patient age, gender, nodule size, type, and ablation parameters, were analyzed. Statistical correlations were evaluated using Spearman’s correlation coefficient and multiple regression analysis. Results: MWA has demonstrated favorable efficacy in treating benign thyroid nodules, with a low incidence of complications. Most nodules experienced significant volume reduction or even complete disappearance after treatment (P < 0.05). The average volume reduction ratio (VRR) of benign thyroid nodules undergoing MWA at 1 month, 3 months, and 6 months post-operation were 52.98%±22.23%, 68.18%±19.81%, and 82.39%±15.03%, respectively, with a significant reduction rate (VRR > 50%) observed in 95.8% (92/96) of the nodules (VRR > 50%). Cystic nodules exhibited the most substantial volume reduction following ablation. The initial volume of the nodule, blood flow status, nodule composition, and the energy absorption per unit volume were all related to the postoperative VRR (P < 0.05). Factors such as patient age, gender, and ablation duration did not show significant correlation with ablation efficacy (P＞0.05). Conclusion: MWA is a promising minimally invasive treatment for benign thyroid nodules. The treatment efficacy is closely related to the initial volume of the thyroid nodule, the composition of the nodule, the blood flow situation of the nodule, and the ablation energy per unit volume.