Treatment efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation for benign thyroid nodules

Abstract

Objective: To evaluate the therapeutic efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation (BRFA) of benign thyroid nodules by comparison with a matched untreated control group.

Methods: The therapeutic efficacy and safety in 35 patients who were subjected to a single session of ultrasound-guided percutaneous BRFA (Group A) for benign thyroid nodules were compared with those in 35 untreated patients (Group B) with benign nodules. The benign nature of all the nodules was confirmed by ultrasound-guided fine-needle aspiration biopsy (FNAB), and all the patients had normal thyroid functions. BRFA was performed with a bipolar electrode (CelonProSurge 150-T20) with an output power of 20 W. Nodule volume, thyroid function and clinical symptoms of all the patients were compared before treatment and during follow-up.

Results: In Group A, the BRFA procedures were completed with a mean time of 10.02 ± 3.30 min (range, 5.47-16.03 min) and with a mean total energy deposition of 10.747 ± 3704 J (range, 5510-17.770 J). The procedures were tolerated well in all the patients without causing any major complications. At the 6-month follow-up, all of the nodule volume decreased significantly (from 8.81 ± 8.66 to 1.59 ± 1.55 ml, p < 0.001) in Group A, whereas the nodule volume increased from 6.90 ± 3.77 to 7.87 ± 3.95 ml in Group B (p < 0.001). All (100%) the 35 nodules in Group A had volume reduction ratios (VRRs) of >50%, among which 3 (8.57%) had VRRs >90%. In Group A, the clinical symptoms of the patients who had symptoms before BRFA disappeared, whereas in Group B, the patients had no resolution of clinical symptoms at the 6-month follow-up.

Conclusion: Ultrasound-guided percutaneous BRFA seems to be an effective and safe method for the treatment of benign thyroid nodules. It may gain a wide use in clinical practice.

Advances in knowledge: Based on the comparable efficacy and clinical symptoms between the BRFA and untreated groups, the technique of BRFA can be used as an effective and safe method for the treatment of benign thyroid nodules.

Figure 1.

A 45-year-old female with a mixed nodule in the left of her thyroid gland. (a) Axial ultrasound examination reveals baseline volume of the nodule (arrow) is 2.15 ml. (b) Axial ultrasound examination of the left thyroid nodule (arrow) volume is 2.78 at the 6-month follow-up visit. A 21-year-old female with a predominantly solid nodule in the left of her thyroid gland. (c) Axial ultrasound examination reveals the nodule (arrow) to be 3.52 ml in volume before bipolar radiofrequency ablation (BRFA). (d) Transverse ultrasound image shows moving-shot technique of the bipolar electrode. Tip of the bipolar electrode is positioned in the nodule (arrow). Hyperechoic gas appears during the ablation procedure. (e) Contrast-enhanced ultrasound after BRFA: the nodule (arrow) shows non-enhancement during the arterial phase. (f) Axial ultrasound examination of the left thyroid nodule 6 months after BRFA. The nodule (arrow) volume is 1.25 ml, with a 64% reduction of initial nodule.

Figure 2.

The mean volume of thyroid nodules in the bipolar radiofrequency ablation (BRFA) (♦) and control (●) groups at enrollment (8.81 ± 8.66 vs 6.90 ± 3.77 ml) and at 1 month (6.22 ± 6.20 vs 6.86 ± 3.71 ml), 3 months (3.87 ± 3.98 vs 7.17 ± 3.79 ml) and 6 months (1.59 ± 1.55 vs 7.87 ± 3.95 ml) after treatment. In contrast to the findings of the control group, significant mean volume reduction is achieved in the BRFA group.