Comparison of Four Ultrasonography-Based Risk Stratification Systems in Thyroid Nodules with Nondiagnostic/Unsatisfactory Cytology: A Real-World Study

• Published in: Cancers 2021-04, Vol.13 (8), p.1948
• Main Authors: Lee, You-Bin, Oh, Young-Lyun, Shin, Jung-Hee, Kim, Sun-Wook, Chung, Jae-Hoon, Min, Yong-Ki, Hahn, Soo-Yeon, Kim, Tae-Hyuk
• Format: Article
• Language: English
• Subjects: Cytology; Iodine; Malignancy; Nodules; Pathology; Performance evaluation; Software; Thyroid; Thyroid gland; Ultrasound
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers13081948

We compared American Thyroid Association (ATA) guidelines, Korean (K)-Thyroid Imaging, Reporting and Data Systems (TIRADS), EU-TIRADS, and American College of Radiology (ACR) TIRADS in diagnosing malignancy for thyroid nodules with nondiagnostic/unsatisfactory cytology. Among 1143 nondiagnostic/unsatisfactory aspirations from April 2011 to March 2016, malignancy was detected in 39 of 89 excised nodules. The minimum malignancy rate was 7.82% in EU-TIRADS 5 and 1.87-3.00% in EU-TIRADS 3-4. In the other systems, the minimum malignancy rate was 14.29-16.19% in category 5 and ≤3% in the remaining categories. Although the EU-TIRADS category ≥ 5 exhibited the highest positive likelihood ratio (LR) of only 2.214, category ≥ 5 in the other systems yielded the highest positive LR of >5. Receiver operating characteristic (ROC) curves of all systems to predict malignancy were located statistically above the diagonal nondiscrimination line (P for ROC curve: EU-TIRADS, 0.0022; all others, 0.0001). The areas under the ROC curve (AUCs) were not significantly different among the four systems. The ATA guidelines, K-TIRADS, and ACR TIRADS may be useful to guide management for nondiagnostic/unsatisfactory nodules. The EU-TIRADS, although also useful, exhibited inferior performance in predicting malignancy for nondiagnostic/unsatisfactory nodules in Korea, an iodine-sufficient area.