Comparison of High Intensity Focused Ultrasound and Radioiodine for Treating Toxic Thyroid Nodules

Luca Giovanella; Arnoldo Piccardo; Cinzia Pezzoli; Fabiano Bini; Riccardo Ricci; Teresa Ruberto; Pierpaolo Trimboli

Disclosures

Clin Endocrinol. 2018;89(2):219-225. 

In This Article

Abstract and Introduction

Abstract

Purpose: We compared the effectiveness of high intensity focused ultrasound (HIFU) and radioiodine (RAI) to treat patients carrying toxic thyroid nodule (TTN). Normalization of serum thyrotropin (TSH) 1 year after treatment was the primary end–point; concurrent changes in nodules' volume and scintigraphic pattern were also evaluated as secondary end–points.

Materials and Methods: Among patients ≥18 years old with TTN observed at our centre between January 1st, 2016 and December 31th, 2016 we prospectively enrolled 17 and 15 age and sex–matched patients treated with RAI and HIFU, respectively. Biochemical thyroid tests and nodules' volume were assessed before and 3, 6 and 12 months after treatments. A thyroid scintigraphy was performed before and 1 year after treatment, respectively.

Results: The final series included 17 patients treated with RAI and 15 patients treated with HIFU, respectively. Neither demographic nor clinical differences were found at baseline. One year after treatment 14 of 17 RAI–treated and 4 of 15 HIFU–treated patients fulfilled criteria for response to treatment (P = .0008). Indeed, the median TSH value was 1.5 IU/mL and 0.2 IU/mL in HIFU and RAI groups, respectively (P < .0001). Finally, despite a similar decrease in nodules' volume in both groups, a scintigraphic response was achieved in 16 of 17 (94%) RAI–treated compared to 8 of 15 (53%) HIFU–treated patients (P = .024), respectively.

Conclusions: In our series, RAI clearly outperforms HIFU in treating patients carrying TTN and remains the first–line noninvasive treatment in such cases.

Introduction

Toxic thyroid nodules (TTN) are the second most common cause of hyperthyroidism after Graves' disease.[1] Radioiodine (RAI) and surgery are both effective treatments for TTN while anti–thyroid drugs are used when RAI and surgery are contraindicated or declined by patients.[2] As complications such as recurrent laryngeal nerve injury and hypoparathyroidism may be observed after surgery, RAI is generally adopted as first–line treatment due to its safety, favourable clinical outcome and relatively low cost.[2,3] However, especially in those countries (as Switzerland) where hospitalization is mandatory, many patients are concerned and frequently require alternatives to RAI. High intensity focused ultrasound (HIFU) thermal treatment was recently proposed to ablate benign nonfunctioning thyroid nodules with associated local symptoms, discomfort and/or cosmetic concerns.[4] The treatment is performed by directing a focused energy ultrasound beam inside the targeted nodule with neither needles nor other invasive instruments.[5] Overall, a reduction in thyroid nodules' volume of ~40% was reported with better results in smaller nodules (ie. <40 mm in the largest diameter).[6–9] Preliminary results in hyperfunctioning nodules were also reported; however, data are sparse and no comparisons between HIFU and RAI treatments are available.[10–12] Since 2016, we propose HIFU to treat both nonfunctioning nodules and TTNs in patients with nodules <40 mm in largest diameter when surgery and/or RAI are contraindicated or declined. This study was carried out to compare the effectiveness of high intensity focused ultrasound (HIFU) and RAI to treat patients carrying TTN.

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