Effects of Microwave Ablation on Papillary Thyroid Microcarcinoma: A Five-Year Follow-Up Report

Some researchers have achieved favorable efficacy in the treatment of primary papillary thyroid microcarcinoma (PTMC) using microwave ablation (MWA). However, as PTMC is a slowly progressing disease, a long follow-up period is required to confirm treatment efficacy. Our study aim was to investigate the long-term efficacy and safety of ultrasound (US)-guided MWA in PTMC. In this study, 41 patients with thyroid masses (41 nodules) were diagnosed with PTMC by fine-needle aspiration or core needle biopsy. They underwent US-guided MWA. Preablation ultrasonic images of the thyroid nodules were collected, and the volumes were measured. The patients had follow-up at 1, 3, 6, and 12 months in the first year and every 6 months from the second year on, after MWA. The volume reduction rates (VRRs) of the thyroid nodules were analyzed. In total, 40 of 41 nodules were completely ablated by MWA. After 60 months of follow-up, the volume significantly decreased from a median of 55.78 mm³ (quartile: 21.50, 112.20 mm³) to 0 mm³ (0, 0 mm³) (p < 0.001), with a VRR of 99.37% ± 4.02%. Two patients developed hoarseness after ablation; one recovered within 10 minutes, and the hoarseness in the other patient resolved 2 months after the ablation. No recurrence, metastatic cervical lymph nodes, or distal metastasis was found during the follow-up period. In this five-year follow-up, MWA presented favorable efficacy with satisfactory safety for the treatment of PTMC. It should be considered an alternative therapy to surgery and active surveillance for solitary PTMC.