Long-term efficacy of ultrasound-guided laser ablation for benign solid thyroid nodules. Results of a three-year multicenter prospective randomized trial

Background: The aim of the present trial on ultrasound (US)-guided laser ablation therapy (LAT) of solid thyroid nodules is to assess long-term clinical efficacy, side effects, and predictability of outcomes in different centers operating with the same procedure.Patients: Two hundred consecutive patients were randomly assigned to a single LAT session (group 1,101 cases) or to follow-up (group 2, 99 cases) at four thyroid referral centers. Entry criteria were: solid thyroid nodule with volume of 6-17 mL, repeat benign cytological findings, normal thyroid function, no autoimmunity, and no thyroid gland treatment.Methods: Group 1: LAT was performed in a single session with two optical fibers, a 1064nm Nd-YAG laser source, and an output power of 3 W. Volume and local symptom changes were evaluated 1, 6,12,24, and 36 months after LAT. Side effects and tolerability of treatment were registered. Group 2: Follow-up with no treatment.Results: One patient was lost to follow-up in each group. Group 1: Volume decrease after LAT was -49 ± 22%, -59 ± 22%, -60 ± 24%, and -57 ± 25% at 6, 12, 24, and 36 months, respectively (P <.001 vs baseline). LAT resulted in a nodule reduction of >50% in 67.3% of cases (P <.001). Local symptoms decreased from 38 to 8% of cases (P =.002) and cosmetic signs from 72 to 16% of cases (P =.001). Baseline size, presence of goiter (P =.55), or US findings (fluid component ≤ 20% [P =.84], halo [P =.46], vascularization [P =.98], and calcifications [P =.06]) were not predictive factors of a volume decrease > 50%. The procedure was well tolerated in most (92%) cases. No changes in thyroid function or autoimmunity were observed. In group 2, nodule volume increased at 36 months (25 ± 42%; P =.04). The efficacy and tolerability of the procedure were similar in different centers.Conclusions: A single LAT treatment of solid nodules results in significant and persistent volume reduction and local symptom improvement, in the absence of thyroid function changes.