Endocrine Abstracts

JOINT445

Background: Determining which thyroid nodules require fine-needle aspiration (FNA) cytology remains a critical challenge in clinical practice. To address this, the Thyroid Imaging Reporting and Data System (TIRADS) was developed, with the two most commonly used formats being the European (EU-TIRADS) and American (ACR-TIRADS) versions. Despite their widespread application, clinical observations indicate that TIRADS 3 nodules measuring ≥20 mm present difficulties in accurate risk stratification. This study aimed to evaluate the efficacy of EU-TIRADS and ACR-TIRADS in differentiating between benign and malignant nodules in this subgroup of nodules.

Material and Methods: Between May 2023 and March 2024, 1,094 patients with thyroid nodules underwent thyroid ultrasound (US) at a University Hospital. Comprehensive data, including clinical parameters, US characteristics, and cytological or histopathological findings, were collected. Nodules measuring ≥20 mm were categorized using EU-TIRADS and ACR-TIRADS, and their predictive performance for malignancy was assessed. Malignancy was confirmed via histopathological examination post-thyroidectomy or through US-guided FNA cytology categorized by the Bethesda classification system.

Results: The study analyzed data from 267 patients (mean age 60.3 ± 14.3 years; 46 men and 221 women) with 308 thyroid nodules. These were classified using EU-TIRADS into categories 3, 4, and 5, with all nodules undergoing FNA. Of the total, 22 nodules were malignant, and 286 were benign. When the EU-TIRADS 3 FNA criteria were adjusted to include thresholds of 25 mm or 30 mm, the rates of avoided FNA procedures were 24% and 41%, respectively. Using the ACR-TIRADS system, 26.6% of FNAs could be avoided (P >0.05). Two malignancies were missed across these adjusted criteria.

Conclusion: The performance of EU-TIRADS and ACR-TIRADS is comparable when the FNA referral diameter threshold for seemingly benign nodules is standardized to 25 mm. Adjusting the EU-TIRADS 3 threshold to 25 mm or 30 mm could significantly reduce unnecessary FNA procedures and healthcare costs. However, the potential trade-off includes an increased risk of missing malignant cases, which underscores the need for careful risk assessment and individualized patient management. Future studies should explore ways to enhance the sensitivity of these grading systems while maintaining efficiency to optimize patient care.