Symptomatic Benign Thyroid Nodules: Efficacy of Additional Radiofrequency Ablation Treatment Session—Prospective Randomized Study

PURPOSE: To prospectively evaluate the efficacy of additional radiofrequency (RF) ablation by comparing the results of one and two sessions. MATERIALS AND METHODS: All patients gave written informed consent to participate in this institutional review board-approved prospective study. From September 2007 to February 2008, 30 patients with benign predominantly solid thyroid nodules causing pressure symptoms and/or cosmetic problems were randomly assigned to undergo single-session (group 1, n = 15) or two-session (group 2, n = 15) RF ablation. RF ablation was performed by using an 18-gauge internally cooled electrode with ultrasonographic guidance. Nodule volume and cosmetic and symptom scores were evaluated before ablation and at 1, 3, and 6 months after initial ablation, and quantitative comparisons of these were performed by using the Mann-Whitney and Wilcoxon signed rank tests; the Spearman rank test was used for correlation between nodule volume reduction and applied energy. RESULTS: At 6-month follow-up, there was significant nodule volume reduction, from 13.3 mL ± 12.9 (standard deviation) to 3.8 mL ± 4.4 in group 1 (P = .001), and from 13.0 mL ± 6.8 to 3.0 mL ± 2.2 in group 2 (P = .001). Each group showed significant improvement in cosmetic (P < .0001) and symptom (P = .001) scores. However, there was no significant difference in volume reduction, cosmetic score, and symptom score between two groups (P = .078, P > .99, and P = .259, respectively). In group 1, three of four patients who had a pretreatment nodule volume larger than 20 mL underwent additional RF ablation because of unresolved clinical problems after the first session. CONCLUSION: Single-session RF ablation showed significant volume reduction and satisfactory clinical response in most patients. Therefore, additional RF ablation should be limited to patients with a large nodule (>20 mL) or unresolved clinical problems.