Treatment Response after Radiofrequency Ablation Alone versus Combined Ethanol Ablation and Radiofrequency Ablation in Predominantly Cystic Thyroid Nodules.

PURPOSE: To compare longitudinal changes in nodule volume after radiofrequency ablation (RFA) alone versus combined ethanol ablation (EA) and RFA in predominantly cystic thyroid nodules (PCTNs), and to estimate the adjusted treatment effect on achieving a volume reduction rate (VRR) ≥85% at 12 months.

MATERIALS AND

METHODS

This retrospective single-center study included 184 PCTNs in 176 patients treated with RFA alone (81 nodules) or combined EA and RFA (103 nodules). Nodule volume was assessed at baseline and at 3, 6, and 12 months. Longitudinal volume changes were analyzed using an inverse probability of treatment-weighted mixed-effects model, and 12-month VRR ≥85% using multivariable-adjusted and weighted logistic regression.

RESULTS

A VRR ≥85% was more frequent after combined treatment at 3, 6, and 12 months (32.0% vs 13.6%, 61.2% vs 40.7%, and 89.3% vs 70.4%, respectively; all P ≤ .006). In the weighted mixed-effects analysis, mean nodule volume was lower with combined treatment at 6 months (difference, -0.81 mL; 95% CI, -1.47 to -0.15; P = .016) and 12 months (difference, -0.86 mL; 95% CI, -1.43 to -0.30; P = .003), whereas the time-by-treatment interaction was not significant (P = .088). Combined treatment was associated with achieving a VRR ≥85% at 12 months in both multivariable analysis (adjusted OR, 4.17; 95% CI, 1.61-11.70; P = .004) and weighted analysis (OR, 2.56; 95% CI, 1.11-5.90; P = .028).

CONCLUSION

After confounder adjustment, combined EA and RFA was associated with higher odds of achieving a VRR ≥85% at 12 months than RFA alone.