Efficacy and Safety of Radiofrequency and Ethanol Ablation for Treating Locally Recurrent Thyroid Cancer: A Systematic Review and Meta-Analysis

Background: The aim of this study was to evaluate the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) for treating locally recurrent thyroid cancer. Materials and Methods: Ovid-MEDLINE and EMBASE databases were searched for studies on the efficacy and safety of RFA and EA for treating locally recurrent thyroid cancer. The pooled proportions of the volume reduction ratio (VRR) 50%, complete disappearance, changes in serum level of thyroglobulin (Tg), recurrence, and complications were assessed using random-effects modeling. Heterogeneity among studies was determined using the chi-square statistic for the pooled estimates and the inconsistency index I-2. To overcome heterogeneity, sensitivity analysis was performed. Results: Ten eligible studies were included, with a total sample size of 270 patients and 415 thyroid nodules. The pooled proportion of VRR 50% after RFA (100%, recalculated 100%; I-2=100%, recalculated I-2=55.3%) was higher than that after EA (89.5%; I-2=82.4%; p=0.2764); the pooled proportion of complete disappearance after RFA (68.8%) was higher than that after EA (53.4%; p=0.3384); and the pooled proportion of recurrence after RFA (0.0%) was lower than that after EA (2.4%, adjusted 1.6%; p=0.9766). However, these differences were not statistically significant. In addition, the pooled proportion of reduction in serum level of Tg after RFA was 71.6% and after EA was 93.8% (p<0.0001). The pooled proportion of complications of both RFA (5.8%, adjusted 1.6%) and EA (1.6%) were low (p=0.8479). The mean number of RFA sessions was <1.3 in five of six RFA studies, and the number of EA sessions was more than two in three of four EA studies. Conclusion: Both RFA and EA are acceptable treatment modalities to manage locally recurrent thyroid cancer in terms of efficacy and safety for poor surgical candidates or those who refuse surgery.