Efficacy of thermal ablation in benign non-functioning solid thyroid nodule: A systematic review and meta-analysis

Background: Image-guided thermal ablations are commonly used in the treatment of thyroid nodules. Radiofrequency ablation (RFA) and laser ablation are the most commonly used. Here we aimed to obtain solid evidence of the long-term efficacy of RFA and laser ablation in benign non-functioning solid thyroid nodules (BNFSTN). Methods: PubMed, CENTRAL, Scopus, and Web of Science were searched until March 2019. Studies reporting the effectiveness of RFA or laser ablation in patients with BNFSTN in terms of volume reduction rate (VRR), compressive symptoms and cosmetic concerns were included. Complications were also assessed. Results: Out of 963 papers, 12 studies on RFA and 12 on laser ablation were included, assessing 1186 and 2009 BNFSTNs, respectively. Overall, VRR at 6, 12, 24, and 36 months was 60%, 66%, 62%, and 53%. VRR of RFA was 68%, 75%, and 87%, respectively. VRR of laser ablation was 48%, 52%, 45%, and 44%, respectively. Baseline volume of nodules undergone RFA was significantly smaller compared to laser ablation (20.1 ± 22.4 versus 24.6 ± 23.6 ml; p < 0.01). Nodules smaller than 30 ml obtained better outcomes than larger ones. A significant reduction in compressive symptoms and cosmetic concerns was found after RFA. Conclusions: This meta-analysis showed that both RFA and laser ablation are able to obtain a significant volume reduction in BNFSTNs. A significant volume reduction is already evident at 6 months after thermal ablation and results are stable over the time.