One year follow-up of US-Guided radiofrequency ablation for low-risk papillary thyroid microcarcinoma: The first experience in Taiwan

BACKGROUND: The incidence of papillary thyroid microcarcinoma (PTMC) has increased rapidly in recent decades, with a favorable overall prognosis. We aimed to evaluate the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for treating low-risk PTMC in Taiwan. METHODS: This prospective study included patients with PTMC who were ineligible or refused surgery and underwent US-guided RFA between October 2018 and June 2020. US and computed tomography (CT) were performed before RFA to assess tumor lesions and exclude cervical lymph node metastasis. Sequential US follow-up following RFA was performed after 1, 3, 6, and 12 months, and yearly thereafter. Volume reduction ratio (VRR) and complete disappearance rate of tumor at one year were evaluated. RESULTS: 13 PTMCs in 12 patients were enrolled with a mean follow-up of 16.2 ± 8.1 months (range, 1-24 months). The median largest tumor diameter and tumor volume before RFA were 0.76 cm and 0.15 ml (range, 0.02-0.37 ml). The median (interquartile range, IQR) volume and VRR at 12 months post-RFA were 0 (0, 0.03) ml (p = 0.033) and 100% (84.26%, 100%) (p = 0.008). Eight tumors (61.54%) were completely disappeared at 12 months post-RFA and no tumor recurrence, lymph nodes, or distant metastasis were noted. All tumors were successfully treated without complications. CONCLUSION: Minimally invasive US-guided RFA is an effective and safe alternative for low-risk PTMC, resulting a satisfied VRR.