Reply:

We have read the letter regarding our recently published article in the American Journal of Neuroradiology¹ and hereby provide a reply. Tez and Tez suggested the issue of incidental small papillary thyroid cancer. A 10% incidence of incidental small papillary thyroid cancer was found in multinodular goiter with benign cytology. To minimize missing cancer, the Korean Society of Thyroid Radiology (KSThR) recommended at least 2 different benign biopsy results before radiofrequency ablation.² In addition, the KSThR recommended careful examination of sonography findings and lymph node metastasis before treatment.³ KSThR also does not recommend thyroid radiofrequency ablation for follicular neoplasms or primary thyroid cancers.² On the basis of these KSThR recommendations, missing cancer was a rare complication after radiofrequency ablation in a large-population multicenter study⁴ and long-term follow-up studies by thermal ablation techniques.^5⇓⇓–8

Regarding complications after surgery and radiofrequency ablation, surgery showed a higher incidence of hypothyroidism than radiofrequency ablation (71% versus 0%) in our study. Because our study included a considerable number of patients with total thyroidectomy (due to bilateral thyroid nodules), hypothyroidism was an inevitable complication in these patients. Hypothyroidism depends on the surgical methods (ie, total thyroidectomy or lobectomy). Regarding the statistical issue, the Wilcoxon signed rank test was used for comparison of the volume reductions between enrollment and the follow-up visit of the radiofrequency group.

The main conclusion of our study was that radiofrequency ablation effectively treats benign thyroid nodules with a low amount of complications.¹ Hence, radiofrequency ablation may be considered as possibly the first-line treatment for benign thyroid nodules. However radiofrequency ablation has a potential limitation of missing incidental small papillary thyroid cancers. This limitation should be carefully validated in the future.

• © 2015 by American Journal of Neuroradiology