Long-term efficacy of ultrasound-guided low power microwave ablation for the treatment of primary papillary thyroid microcarcinoma: a 3-year follow-up study

To evaluate the safety and efficacy of ultrasound-guided low-power microwave ablation (MWA) for the treatment of papillary thyroid microcarcinoma (PTMC) with a 3-year follow-up. A total of 21 nodules diagnosed as PTMC from the 15 patients were performed with MWA at a power of 20 W. The images of the nodules were recorded by ultrasound before MWA and 1, 3, 6, 12 months after MWA, and every 6 months thereafter, respectively. The volumes of the nodules were compared before MWA and at each follow-up point after MWA. The volume reduction rate (VRR) of nodules was also calculated. The mean volume of the nodules was 134.3 +/- 129.8 mm(3) initially (the range was 7.4-423.8 mm(3)), which decreased significantly to 2.3 +/- 10.5 mm(3) (the range was 0-48.1 mm(3)) of the ablation area (P = 0.000) at the follow-up point of 36 months with a mean VRR as 98.78 +/- 5.61% (the range was 74.28-100%). During the follow-up period (the range was 36-48 months), 20 of the 21 nodules were completely absorbed and no recurrent nodule was found. After a long-term follow-up of 3 years, the low power MWA showed a good safety and efficacy for the treatment of PTMC. In addition to surgery and active surveillance, MWA might be another alternative for patients with PTMC.