Association between microwave ablation and remission in patients with Graves' hyperthyroidism receiving continuous antithyroid drug treatment: a single-arm prospective study.

Background: Graves' disease (GD) is the most common cause of hyperthyroidism. Nearly half of patients develop persistent/recurrent GD (prGD) after antithyroid drug (ATD) therapy. Microwave ablation (MWA) is a precise minimally invasive therapeutic modality; however, evidence regarding its efficacy for prGD remains limited. This study therefore evaluated the efficacy of MWA in treating prGD and investigated factors predictive of post-MWA remission. Methods: This single-arm prospective study enrolled 45 patients with prGD who underwent bilateral thyroid MWA under ultrasound guidance at the Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine between January 2023 and April 2024. The primary outcome was the remission rate during follow-up, defined as maintenance of normal thyroid function for at least 6 months after ATD discontinuation. Kaplan-Meier analysis with the log-rank test was used to analyze remission, and logistic regression and receiver operating characteristic (ROC) curve analyses were used to identify factors associated with remission. Results: The cohort included 34 females and 11 males, with a median follow-up of 31.00 (28.00, 33.00) months. Notable findings included a significant reduction in the median thyroid-stimulating hormone (TSH) receptor antibody level at the last follow-up (P<0.001). Both thyroid volume and the average methimazole (MMI) dose were significantly reduced (both P<0.001). At the last follow-up, remission was achieved in 29 patients, yielding a total remission rate of 64.44%. Patients in the remission group had smaller baseline thyroid volumes than those in the non-remission group. Preoperative thyroid volume was independently associated with remission [odds ratio (OR) =0.829; 95% confidence interval (CI): 0.707-0.971; P=0.020], with an optimal cutoff of 29.35 mL [area under the curve (AUC) =74.4%; 95% CI: 0.596-0.892; sensitivity =72.4%; specificity =68.7%]. All nine patients with thyroid volumes less than 20 mL achieved remission. No severe complications were reported during the follow-up period. Conclusions: MWA was associated with decreased thyroid volume and reduced MMI dosage in patients with prGD, and clinical remission was observed in a subset of these patients. A preoperative thyroid volume of less than 29.35 mL is associated with a higher likelihood of remission.