Diagnostic performance of US-based FNAB criteria of the 2020 Chinese guideline for malignant thyroid nodules: comparison with the 2017 American College of Radiology guideline, the 2015 American Thyroid Association guideline, and the 2016 Korean Thyroid Association guideline

Background: To investigate the diagnostic performance of the ultrasonography-based fine-needle aspiration biopsy criteria of the Chinese Thyroid Imaging Reporting and Data System (C-TIRADS) for malignant nodules compared to 3 other guidelines. Methods: This study included 2,309 thyroid nodules in 1,697 patients with histopathological and cytopathological diagnoses of benign and malignant nodules from January 2018 to August 2020. The clinical and ultrasonographic features of the nodules were retrospectively reviewed and classified according to the Chinese guideline (C-TIRADS), the American College of Radiology guideline (ACR-TIRADS), the American Thyroid Association guideline (ATA guideline), and the Korean Thyroid Association guideline (K-TIRADS). The diagnostic performance of the guidelines and their unnecessary fine-needle aspiration biopsy rates were calculated using randomized, blinded trials. Results: Of the 2,309 nodules, 1,418 (61.4%) were benign and 891 (38.6%) were malignant, with 884 (99.21%) papillary carcinomas. The accuracy of C-TIRADS was 84.71%, followed by the guidelines of ACR-TIRADS (82.11%), K-TIRADS (81.64%), and the ATA guideline (78.56%). Furthermore, the area under the receiver operating characteristic curve (AUC) was the highest for the C-TIRADS (0.905). Similar results were revealed for both the diagnostic performance and AUC of nodules smaller and larger than 10 mm. The ACR-TIRADS showed the lowest unnecessary biopsy rate (17.54%), followed by the C-TIRADS (22.61%), ATA guideline (27.90%), and the K-TIRADS (28.67%). Conclusions: The C-TIRADS demonstrated high diagnostic performance and a relatively low unnecessary biopsy rate in detecting thyroid cancer compared to the 3 other guidelines. However, further understanding of the ultrasonography-based fine-needle aspiration biopsy criteria of the C-TIRADS should be gained in the future.