ACR TI-RADS Score combined with cytopathology classification improves the risk stratification of indeterminate thyroid nodules

BACKGROUND: The aim of this retrospective study was the elaboration of a new diagnostic model that integrate cytological reports (2017 Bethesda System for Reporting Thyroid Cytopathology) with ultrasonographic features (based on ACR TI-RADS score) to achieve a more accurate definition of indeterminate thyroid nodule malignancy risk. METHODS: Ninety patients submitted to thyroidectomy were divided in three classes: low malignancy risk (AUS/FLUS with TI-RADS 2/TI-RADS 3 and FN/SFN with TI-RADS 2), intermediate malignancy risk (AUS/FLUS with TI-RADS 4/TI-RADS 5 and FN/SFN with TI-RADS 3/TI-RADS 4), and high malignancy risk (FN/SFN with TI-RADS 5). RESULTS: The surgical approach should be recommended in high-risk patients (81.82% of malignancies), carefully evaluated in intermediate risk (25.42%), whereas a conservative approach can be adopted in low-risk patients (0.00%). CONCLUSIONS: The integration of these two multiparametric systems in a Cyto-US score has proven to be a feasible and reliable aid to achieve a more accurate definition of malignancy risk.