Abstract

Background: Large benign thyroid nodules (LBNs) frequently cause compressive or cosmetic symptoms despite their benignity. Accurate risk stratification combining sonographic and cytological criteria is crucial for appropriate management and selection for minimally invasive therapies such as radiofrequency ablation (RFA).

Methods: In this cross-sectional study (ClinicalTrials.gov Identifier: NCT07115576), 150 patients with 174 thyroid nodules ≥20 mm, cytologically confirmed as benign (Bethesda II), were enrolled at the Center of Endocrinology and Diabetes, Family Hospital, Da Nang, Vietnam. Clinical, biochemical, and sonographic features were systematically assessed and categorized according to the ACR-TIRADS system. The study was part of the SS-RFAT trial (ClinicalTrials.gov Identifier: NCT07115576)

Results: The cohort was predominantly female (85.3%) with a mean age of 44.2 ± 14.8 years. The mean largest nodule diameter was 31.7 ± 10.3 mm. Most nodules were solid (75.8%) and isoechoic (47.7%), with smooth margins (98.3%) and wider-than-tall shape (99.4%). Suspicious sonographic features were rare (microcalcifications 2.3%, irregular margins 1.7%). All nodules were cytologically benign. Thyroid function was largely normal (TSH 1.27 ± 0.8 mIU/mL; FT4 1.28 ± 0.3 ng/dL).

Conclusions: Large thyroid nodules frequently exhibit benign sonographic and cytological characteristics. Integrating ACR-TIRADS and Bethesda classifications allows accurate exclusion of malignancy and supports the safe selection of patients for nonsurgical treatments such as RFA.