Endocrine Abstracts

Objective: The aim of this study was to evaluate the capability of the thyroid nodule ultrasonography criteria of the European Thyroid Imaging and Reporting Data System (EU-TIRADS) to predict fine needle aspiration cytology results categorised by The Bethesda system.

Methods: A retrospective analysis was made out of 310 cases of an outpatient clinic over a period of 1 year (2018.03–2019.03). We compared single-specialist-performed thyroid nodule ultrasonography findings categorised by EU-TIRADS to the cytopathology results of fine needle aspiration that we assigned to specific Bethesda categories. The thyroid nodules were divided into benign with ultrasonography findings of EU-TIRADS 2–3 and cytopathology of Bethesda 2 and malignant with EU-TIRADS 5 and Bethesda 5–6. Statistical analysis was performed using SPSS 23.0.

Results: We assembled cases of 310 people of which 279 (90%) were female and 31 (10%) were male. 4 patients were assigned to benign (EU-TIRADS 2), 191 low-risk (EU-TIRADS 3), 68 intermediate-risk (EU-TIRADS 4) and 47 high-risk (EU-TIRADS 5) category on ultrasonography. Overall concordance rate of EU-TIRADS and fine needle aspiration findings was 75.48%. The probability of benign pathocytology result in EU-TIRADS 2, 3, 4 and 5 was 100%, 95.3%, 72.1% and 38.3% respectively. At the same time the risk of finding a malignant cytology result was 0% with EU-TIRADS 2, 1.1% with EU-TIRADS 3, 13.2% with EU-TIRADS 4 and 38.3% with EU-TIRADS 5. Specificity and sensitivity was 91.2% and 90% accordingly. The positive predictive value was 50% and the negative predictive value was 98.9%. The association between EU-TIRADS and fine needle aspiration findings was good according to the ROC curve and the area under the curve with 0.879.

Conclusions: The categories of thyroid nodule malignancy risk in EU-TIRADS have a good correspondance to Bethesda cytopathologic categories. Concordance between the benign ultrasonography and cytology criteria is more significant compared to malignant. With every higher category of EU-TIRADS the probability of malignant cytology result increases.

Keywords: fine-needle aspiration biopsy, The Bethesda System, EU-TIRADS, thyroid nodule.