Abstract
BACKGROUND: Radiofrequency ablation (RFA) has gained recognition as a highly effective treatment for benign thyroid nodules (BTNs). However, post-procedural thyroid function changes have been reported. OBJECTIVES: This study specifically focuses on the potential link between changes in thyroid function and the volume reduction ratio (VRR) of treated nodules. Additionally, it seeks to evaluate whether fluctuations in thyroid function at mid-term follow-up can serve as early indicators for the development of long-term hypothyroidism following RFA. DESIGN: Retrospective cohort study. METHODS: In this study, 50 euthyroid individuals (mean age = 47.1 years; 43 females, 7 males) with a total of 72 BTNs (median volume = 4.61 mL) undergoing RFA were evaluated. Comprehensive assessments, including clinical examinations, ultrasound imaging, and blood tests, were conducted at specific intervals (pre-RFA, and at 6 months, 12 months, and annually post-RFA). RESULTS: The mean follow-up period was 22.3 months. Both medium-term and long-term follow-ups revealed significant reductions in triiodothyronine (T3) levels (p = 0.010, p = 0.036) and elevations in thyroid-stimulating hormone (TSH) levels (p < 0.001, p = 0.006) compared to baseline measurements. A negative correlation was found between medium-term T3 levels and long-term VRR (r = -0.475, p = 0.001). Furthermore, patients with lower T3 levels during medium-term follow-up demonstrated a significantly higher long-term VRR compared to those with higher T3 levels (0.89 vs 0.77, p = 0.030). CONCLUSION: Following RFA, notable alterations in thyroid function were observed, without meeting the criteria of hypothyroidism. Additionally, a lower mid-term T3 level may be indicative of a better VRR during long-term follow-up.