Background: The CUT score is a thyroid nodule scoring system that has become recently available as a smartphone application. It has been created on the basis of a clinical (C) and ultrasonographic (U) meta-analysis of suspicious thyroid nodule features to help clinicians with the preoperative malignancy risk assessment of thyroid nodules. The aim of the present study was to analyze the C + U sum of the CUT score for cytologically indeterminate TIR3A and TIR3B thyroid nodules, comparing the results obtained from the two groups. Methods: The CUT score was applied to 201 cytologically indeterminate thyroid nodules, 78 categorized as TIR3A and 123 as TIR3B. The Mann-Whitney test was applied to compare the C + U score values of the two groups, and a receiver operating characteristic (ROC) curve analysis was performed to validate the C + U score as a diagnostic test. Results: In both groups, the median C + U value of all nodules was significantly higher in case of malignant (4.37 TIR3A, 4.50 TIR3B) versus benign nodules (2.75 TIR3A, 3.00 TIR3B). Through ROC curve analysis within the TIR3A group, a C + U value ≥4.00 was determined as diagnostic cutoff for the detection of malignant nodules (56% sensitivity, 77% specificity, area under the curve [AUC] = 0.714); and for the TIR3B group, a cutoff of C + U value of ≥3.75 was identified (65% sensitivity, 78% specificity, AUC = 0.744). Conclusion: The CUT score could represent a valid aid for the clinician in the management of indeterminate nodules with follicular proliferation.
Keywords: indeterminate; risk of malignancy; scoring system; thyroid nodule; ultrasonography.