Comparison of microwave alone and combined with ethanol ablation for different types of benign cystic solid thyroid nodules

Abstract Objective To evaluate the efficacy and safety of microwave ablation (MWA) plus ethanol ablation (EA) for different types of benign cystic solid thyroid nodules.Methods A total of 81 patients with 81 benign cystic solid thyroid nodules were enrolled into the study; 39 were divided to the MWA group and 42 to the combined group (MWA combined with EA). Nodule inactivation rate, volume reduction rate (VRR) and surgical complications of all patients were analyzed before and after treatment.Results The mean inactivation rate were 86.49 ± 6.68% and 90.09 ± 5.79% in the microwave and combined groups respectively, and the inactivation rate of nodule decreased as the nodule volume increased. For nodules ≥ 15 ml in volume, the mean inactivation rate of the combined group was higher than that of the microwave group (all P < 0.05). The mean VRR at 12 months postoperatively was 89.58 ± 4.32% in the microwave group and 92.92 ± 3.49% in the combined group, showing statistical significantly different between both arms (P = 0.001). The combined group decreased in volume more significantly than the microwave group for nodules with 20%-50% or 50%-80% cystic proportions or > 15 ml in volume (all P < 0.05). The complication rate was 23.08% and 2.38% respectively.Conclusion MWA combined with EA is more effective than MWA for treating cystic solid thyroid nodules. MWA combined with EA may be the first approach for nodules with > 20% cystic proportions or volume > 15 ml.