Safety and Feasibility of US-guided Microwave Ablation for the Treatment of Bethesda III Thyroid Nodules with Negative Eight-Gene Panel Mutational Profile

Purpose To evaluate the safety and efficacy of US-guided thermal ablation in the treatment of Bethesda III thyroid nodules with negative eight-gene panel testing results. Materials and Methods This retrospective single-center study included patients with thyroid nodules diagnosed as Bethesda category III (atypia of undetermined significance) at fine-needle aspiration biopsy and with negative eight-gene testing results who were treated with US-guided microwave ablation (MWA) between July 2020 and September 2023. Incidence of complications, technical success rate (TSR), volume reduction rate (VRR), nodule recurrence, and thyroid function were evaluated over a follow-up period of 2 years. Data before and after MWA were compared using variance analysis and the Cochran-Mantel-Haenszel χ² test. Results A total of 101 Bethesda III nodules were detected in 95 patients (mean ± SD age, 47.08 years ±14.63; 79 female patients, 16 male patients), all of which were completely ablated (100% TSR). Two patients experienced mild neck swelling and pressure sensation after the minimally invasive operation, and the incidence of postoperative complications was 2% (two of 95). None of the patients experienced tumor recurrence or progression. At 2-year follow-up, the mean VRR of the ablated area was 90.88% ± 13.59 in 15 patients; 87% (13 of 15) of these patients had a 100% VRR. There was no evidence of a difference in thyroid function before and after MWA from 1 to 24 months (<i>P</i> = .15-.99). Conclusion US-guided MWA was safe and effective for the treatment of Bethesda III thyroid nodules with negative eight-gene panel testing results. <b>Keywords:</b> Ablation Techniques, Radiation Therapy/Oncology, Head/Neck, Thyroid, Safety, Observer Performance Published under a CC BY 4.0 license.