Endocrine Abstracts

Background: Several ultrasound (US) scoring systems have been proposed to provide rules for standardizing risk stratification of thyroid nodules and to select which nodules should have a fine needle aspiration (FNA) biopsy performed. TI-RADS classification is one of the most used in the daily practise. Recently, EU-TIRADS scoring system has been published to simplify the evaluation of thyroid nodules and to integrate previous classifications into a single system. We aimed to compare these two scoring systems (TI-RADS and EU-TIRADS) and to assess the correlation between the ultrasonography TI-RADS/EU-TIRADS classification systems and histopathology.

Methods: Observational, retrospective study of patients with thyroid nodules who underwent thyroidectomy at our centre between January and October 2018. Nodules were categorised according to TI-RADS and EU-TIRADS classification. After thyroidectomy, histopathological results were correlated with the US findings.

Results: We included 61 patients (79% females, age 55.4±14.6 years old) with 89 nodules. Of all the nodules, 74 (83%) were benign, whereas 15 (17%) were malignant. The benignity percentages of TI-RADS category 2, 3, 4A, 4B and 5 were 100%, 100%, 91%, 68% and 0%, respectively. No malignant nodules were classified in category 2 or 3 (P<0.001). In relation to EU-TIRADS, the benignity percentages of category 2, 3, 4 and 5 were 100%, 97%, 91% and 0%, respectively. No malignant nodules were classified in category 2 (P<0.001). The size of the the malignant nodule classified as EU-TIRADS 3 was 40 mm, so FNA would have been indicated in this nodule. When compared with histopathological results, sensitivity, specificity, positive predictive value and negative predictive value were 100%, 39%, 25% and 100%, respectively, for TI-RADS; and 94%, 72%, 40% and 98%, respectively, for EU-TIRADS.

Conclusion: Our results show that TI-RADS demonstrated a higher sensitivity, whereas EU-TIRADS had a higher specificity; besides, it is easier to use in daily practice. Moreover, EU-TIRADS also considers the nodule size as a criterion for FNA, which increases the sensitivity of this classification.