Assessment of thermal ablation for treating Bethesda IV thyroid nodules: a systematic review and meta-analysis

Background: This study aimed to evaluate the efficacy and safety of thermal ablation in the treatment of patients with Bethesda IV thyroid nodules (follicular neoplasms) by analyzing large-scale data on various outcomes.

Materials and methods: Literature searches were conducted in PUBMED, EMBASE, Web of Science, and the Cochrane Library for studies on the use of thermal ablation in patients with Bethesda IV thyroid nodules published from March 1, 2014, to March 1, 2024. Data on volume change at 12 months; the volume reduction rate (VRR) at 1, 3, 6, and 12 months; the complete disappearance rate (CDR); and the complication rate were evaluated. All the data were analyzed with STATA 15.

Results: Five eligible studies were included. The findings indicate that thermal ablation is both effective and safe. The mean change in tumor volume at 12 months postthermal ablation was characterized by a standardized mean difference (SMD) of -1.13 (95% CI: -1.36 - -0.90, p = 0.000). Specifically, the mean changes in tumor volume at 12 months after radiofrequency ablation (RFA) and microwave ablation (MWA) were - 1.19 (95% CI: -1.75 - -0.64) and - 1.26 (95% CI: -1.71 - -0.81), respectively. The VRRs at 1, 3, 6, and 12 months postthermal ablation were 43% (95% CI: 33 - 53%), 47% (95% CI: 20 - 74%), 69% (95% CI: 62 - 76%), and 85% (95% CI: 79 - 90%), respectively. The VRRs at 12 months after RFA and MWA were 84% (95% CI: 76 - 91%) and 85% (95% CI: 75 - 95%), respectively. The VRR at 12 months, stratified by initial nodule size, was 84% (95% CI: 77 - 91%) and 86% (95% CI: 78 - 94%). The CDR at the final follow-up was 88% (95% CI: 80 - 95%). The complication rate was 4.0% (95% CI: 0.0 - 8.0%), with pain and hoarseness being the most frequently reported complications; no life-threatening complications were documented.

Conclusions: Thermal ablation is a reliable treatment for Bethesda IV thyroid nodules, and RFA and MWA are advantageous treatment strategies. However, more prospective, multicenter, and large-sample studies are needed in the future.