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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.