Efficacy of Ethanol Ablation for Benign Thyroid Cysts and Predominantly Cystic Nodules: A Systematic Review and Meta-Analysis

Abstract

Background: Ultrasound-guided minimally invasive procedures are widely used to treat thyroid diseases. The objective of this study was to assess the efficacy and safety of ethanol ablation (EA) in comparison with other non-surgical options in the treatment of benign thyroid cystic nodules.

Methods: We conducted a systematic search of studies on EA for thyroid cystic nodules, mainly in the Ovid-MEDLINE and Embase, Web of Science, and Cochrane databases. The standardized mean difference (SMD) of the volume reduction ratio (VRR) after EA versus other non-surgical treatments comprised the primary outcome, whereas the odds ratio (OR) of therapeutic success rates between the two groups comprised the secondary outcome.

Results: The meta-analysis included 19 studies (four randomized controlled trials and 15 non-randomized studies) with 1,514 participants. The cumulative VRR of EA was 83.908% (95% confidence interval [CI], 79.358% to 88.457%). EA had a significantly higher pooled VRR (SMD, 0.381; 95% CI, 0.028 to 0.734; P=0.030), but not a significantly higher pooled therapeutic success rate (OR, 0.867; 95% CI, 0.132 to 5.689; P=0.880), than other forms of non-surgical management including radiofrequency ablation (RFA), polidocanol sclerotherapy, and simple aspiration with or without saline flush. However, the VRR and therapeutic success rate were not significantly different between EA and RFA. Major complications were recorded only in six patients (0.53%) with self-limiting dysphonia.

Conclusion: The role of EA as the first-line treatment for benign thyroid cysts and predominantly cystic nodules is supported by its high effectiveness and good safety profile compared to other currently available non-surgical options.

Keywords: Ablation techniques; Cyst; Ethanol; Meta-analysis; Sclerotherapy; Thyroid nodule.

Fig. 1

Flow diagram summarizing the literature review process according to the Preferred Reporting Items for Systemic Reviews and Meta-Analysis (PRISMA) guideline. VRR, volume reduction ratio; EA, ethanol ablation.

Fig. 2

Summary of quality assessment of the included randomized controlled trials according to Risk-of-Bias tool 2.0 (RoB 2.0) (A), and non-randomized studies according to Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS) (B).

Fig. 3

Forest plots summarizing the efficacy of ethanol ablation (EA) in treating cystic thyroid nodules measured by the volume reduction ratio as compared with other types of non-surgical management, overall effects, and subgroup analysis according to different comparators (A) and cysts versus predominantly cystic thyroid nodules (PCTNs) (B). SD, standard deviation; IV, inverse variance method; CI, confidence interval; RFA, radiofrequency ablation.

Fig. 4

Forest plots summarizing the therapeutic success rate of ethanol ablation (EA) as compared with other types of non-surgical management, overall effects, and subgroup analysis according to different comparators (A) and cysts versus predominantly cystic thyroid nodules (PCTNs) (B). M-H, Mantel-Haenszel; CI, confidence interval; RFA, radiofrequency ablation.

Fig. 5

Funnel plots of studies that evaluated the volume reduction ratio. SE, standard error; SMD, standardized mean difference; EA, ethanol ablation; RFA, radiofrequency ablation.