Accuracy of the ‘CUT’ Score for Assessing Malignancy in Bethesda 3 and 4 Thyroid Nodules in North American Population: A Retrospective Study

Abstract

Background

The CUT score is a thyroid nodule malignancy risk assessment scoring system intended to guide surgeons in treating Bethesda 3 and 4 thyroid nodules. It is based on clinical (C) and ultrasonographic (U) features and a five-tiered (T) representing cytology.

Purpose

Our study aimed to assess the utility of the CUT score in predicting thyroid malignancy in the North American population. The main reason for creating this score is to reduce unnecessary surgeries on these challenging thyroid nodules.

Materials and Methods

A retrospective record review study applied the CUT score to 219 Bethesda 3 and 4 thyroid nodules. A total of 203 Bethesda 3 and 16 Bethesda 4 nodules from patients treated between January 2015 and December 2019 at a single institution were assessed. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the CUT diagnostic test. Binary logistic regression analysis was performed. Iteration of analysis was performed after stratification according to body mass index to assess CUT score accuracy in obese and non-obese patients.

Results

Of 219 nodules analyzed, 148 were characterized as benign and 71 as malignant. Prevalence rates of malignancy were 29.6% (n = 60) and 68.8% (n = 11) in Bethesda 3 and 4 nodules, respectively. The mean CU (clinical, ultrasonography) score was 5.35 ± 1.38 in benign nodules versus 4.96 ± 1.5 in malignant nodules (p = 0.08). The area under the curve (AUC = 0.433) for the association of CUT scores with nodule malignancy was not significant (p = 0.13). The CUT score was insignificant as a diagnostic test for nodule malignancy in obese (AUC = 0.45; p = 0.72) and non-obese patients (AUC = 0.39; p = 0.08).

Conclusion

The CUT score did not correlate with preoperative malignancy risk estimates in Bethesda 3 thyroid nodules and, therefore, may have limited utility as a predictor of malignancy in these thyroid nodules.

Keywords:

• Thyroid nodule
• CUT score
• Bethesda
• scoring system
• ultrasound
• FNA
• indeterminate nodule
• AUS
• FLUS
• Follicular neoplasm

Declaration of interest

Areej Shihabi, Mohammad Hussein, Eman Toraih, Abdallah Attia, Mohanad Youssef, Ahmed Elnahla, Mahmoud Omar, Mohamed Shama, Ralph Corsetti, Emad Kandil, all authors declare the absence of conflict of interest.