RESUMEN
<p><b>OBJECTIVE</b>To evaluate the clinical efficacy of ultrasound-guided lauromacrogol sclerotherapy for benign thyroid cysts and analyze the factors affecting the efficacy.</p><p><b>METHODS</b>Ultrasound-guided lauromacrogol sclerotherapy was performed in 97 patients with a total of 99 benign thyroid cysts. The changes in cystic volume and other thyroid parameters were evaluated at 1, 3, 6, and 12 months after sclerotherapy. According to changes in the cystic volume, the efficacy of sclerotherapy was defined as therapeutic failure (with a volume reduction <50%), treatment success (volume reduction ≥50%) and cure (volume reduction ≥90%). The factors of affecting the efficacy of sclerotherapy was analyzed using COX regression.</p><p><b>RESULTS</b>The mean cystic volume at 1, 3, 6 and 12 months after sclerotherapy were reduced from the baseline volume of 12.08∓11.56 cmto 5.63∓8.51 cm, 5.96∓8.42 cm, 3.80∓5.50 cmand 2.85∓3.98 cm, respectively, with an average cystic volume reduction rate of (70.02∓33.72)%. Therapeutic success was achieved 82 of the 99 cysts (82.83%) and cure was achieved 63cysts (63.64%) at 12 months after the procedure. A second sclerotherapy was performed for 13 cysts which did not show a volume reduction at 1-3 months after the initial procedure. A disease course of over 12 months was an independent risk factor for a second sclerotherapy (23.7% [9/38] vs 6.6% [4/61], OR=4.473 [1.238-16.169], P=0.022). The efficacy of sclerotherapy was related to cystic cavity separation, cystic fluid viscosity, cystic/solid ratio and cystic wall thickness. COX regression analysis revealed that cystic cavity separation (HR=2.25, 95%CI: 1.19-4.25) and cystic fluid viscosity (HR=2.02, 95%CI: 1.19-3.43) were the major factors affecting the treatment efficacy.</p><p><b>CONCLUSION</b>Ultrasound-guided lauromacrogol sclerotherapy is effective and safe for treatment of benign thyroid cysts, and the maximal treatment effect can be achieved at 6 months after sclerotherapy and in cases of uncomplicated cysts with non-viscous cystic fluid, no solid cystic cavity separation and a disease course of less than 12 months.</p>