RESUMO
OBJECTIVE: To prospectively evaluate the efficacy of lauromacrogol injection for ablation (LIA) of benign predominantly cystic thyroid nodules and its related factors. MATERIALS AND METHODS: A total of 142 benign predominantly cystic thyroid nodules (median volume, 12.5 mL; range, 0.4-156 mL) in 137 patients (male:female sex ratio, 36:101; mean age ± standard deviation [SD], 49 ± 13 years) were treated with LIA after being confirmed as benign via cytology. The volume reduction rate (VRR) of the nodules and cosmetic score were evaluated during follow-up at 1, 3, and 6 months after treatment and every 6 months thereafter. A VRR of ≥ 50% at the 12-month follow-up was considered to indicate effective treatment. The associations between the clinical factors and nodular ultrasound features, including the initial nodule volume, proportion of solid components, vascularity grade and ineffective treatment (VRR of < 50% at the 12-month follow-up), and regrowth were analyzed. RESULTS: All patients completed follow-up for at least 12 months. The average ± SD follow-up period was 32 ± 11 months (range, 12-54 months). The effective treatment rate was 73.2% (104/142), while the regrowth rate was 12.0% (17/142) at the last follow-up. Grade 2-3 intranodular vascularity in the solid components of the nodules was the only independent factor associated with ineffective treatment, with an odds ratio (reference category, grade 0-1) of 3.054 (95% confidence interval, 1.148-8.127) (p = 0.025). CONCLUSION: LIA is an effective treatment for predominantly cystic thyroid nodules. Grade 2-3 intranodular vascularity in the solid components of nodules is the only independent risk factor for ineffective LIA.