Early second radiofrequency ablation treatment gave rise to significantly greater nodule shrinkage at 12 months than single-session treatment for large-volume benign thyroid nodules.

Introduction: Radiofrequency ablation (RFA) is an effective nonsurgical treatment for symptomatic benign thyroid nodules. Large-volume nodules (≥20-mL) often require 2 or more radiofrequency ablation sessions to achieve desirable shrinkage but the optimal interval between sessions remains unknown. We hypothesized that early (within 6 months) retreatment could improve nodule shrinkage. This study compared the 12-month volume reduction rate (VRR) and complications between single-session radiofrequency ablation and 2-session radiofrequency ablation within 6 months for large benign thyroid nodules.

Methods: Consecutive patients with cytologically proven benign thyroid nodules ≥20 mL undergoing radiofrequency ablation were prospectively assigned to undergo either single-session (group 1) or 2-session radiofrequency ablation within 6 months (group 2). All were followed up for at least 12 months after the initial radiofrequency ablation. Volume reduction rate was calculated as (baseline - current volume)/baseline volume × 100%. Complications were documented.

Results: Out of 67 nodules ≥20 mL that underwent radiofrequency ablation, 43 nodules (group 1: n = 23, group 2: n = 20) from 42 patients were analyzed. Both groups had comparable baseline nodule volumes (33.2 ± 14.9 mL vs 34.3 ± 12.5 mL) and clinical parameters (P > .05). The 6-month volume reduction rate was comparable (65.7 ± 13.2% vs 68.6 ± 13.3%, P = .264) but the 12-month volume reduction rate was significantly greater in group 2 (65.9 ± 17.1% vs 75.6 ± 11.5%, P = .019). Group 2 nodules continued to shrink from 6 to 12 months (P = .012), whereas group 1 nodules did not (P = .503). Two-session radiofrequency ablation within 6 months was the only significant factor associated with a 12-month volume reduction rate of ≥75% (odds ratio 4.375, 95% confidence interval 1.210-15.812, P = .024). No vocal cord paresis or hematoma requiring reoperation occurred.

Conclusion: Early retreatment with 2-session radiofrequency ablation within 6 months was safe and led to significantly greater nodule shrinkage at 12 months than single-session radiofrequency ablation.