The efficacy of Radiofrequency Ablation in the treatment of benign thyroid nodules and recurrent well-differentiated thyroid carcinomas.

Purpose: The aim of our study was to evaluate, in our experience, the effectiveness of the Radiofrequency Ablation (RFA)in the treatment of benign thyroid nodules and thyroid malignancies. Materials and methods: The study included 23 patients, 15 with nodular goiter (NG) with contraindication or refusing surgery and 8 with inoperable recurrent well-differentiated thyroid cancers (RTC). RFA was performed in a single session under ultrasound guidance, under local anesthesia and mild sedation using 18- or 19-gauge internally cooled, single tipped electrode with 7- and 10-mm active tips. The pre- and post-treatment evaluations included: contrast-enhanced ultrasound (CEUS) and unenhanced Computed Tomography (CT) study for the NGs, completed with contrast media in patients with RTCs. Of each lesion the initial volume (V), the vascularity and the proportion of solid component were assessed; for NGs we also evaluated thyroid function, local symptoms (according to a score of 0-10 severity) and a cosmetic score defined by the radiologist according to a 1-4 scale (not palpable, palpable but not visible, visible only during swallowing and visible in any position). The follow-up in 21/23 patients ranged between 6 and 18 months; 2/8 patients with RTCs did not undergo 6-months follow-up, respectively for systemic progression of disease and onset of severe comorbidity. Volume Reduction Rate was assessed during the follow-up and therapeutic success was defined as a> 50% VRR. Residual vital tissue was also assessed by using CEUS or post-contrastographic CT examinations. Complications were also evaluated. For NGs we also tried whether there was a correlation between VRR at 6 months follow-up and some parameters such as age, gender, mean energy per millilitre of pre-treatment nodule volume, nodule initial volume, initial nodule solidity and initial nodule vascularity. Results: Mean V of lesions before treatment was 29.5 ± 24.7 mL for NGs (range: 5.5-90ml), and 4.7 ± 3.5 ml (range: 0.8 to 8.8 ml) for RTCs. The mean VRR at 6, 12 and 18 months were respectively 74.3%, 79.8% and 82.3% for NGs. At last follow-up, the therapeutic success rate of NGs was 100% (15/15). The overall recurrence rate was 0% (0/15). We found that volume, residual vital tissue, cosmetic score and symptom score of NGs were significantly lower at last follow-up than before treatment (P <0.0005 for all comparison). Initial nodule volume, vascularity and energy delivered per millilitre of pre-treatment nodule volume demonstrated to be significantly related to 6-months VRR (P < 0.0001 for all analysis). The VRR of RTCs was 68.4%, 66.4% and 64.4% during the follow-up at 6, 12 and 18 months. At last follow-up, the therapeutic success rate for RTCs was 83% (5/6) with overall regrowth and/or recurrence rate of 0% (0/6). In no case of NGs dysphonia was observed; 3/6 patients with paratracheal RCT, closely adjacent to the danger triangle of the recurrent laryngeal nerve, have reported dysphonia (permanent in 2 cases and transient in 1 patient). Conclusions: RFA demonstrated in our experience to be an effective and safe interventional technique and may represent a viable alternative to surgery in selected patients