Comparison of the C-TIRADS, ACR-TIRADS, and ATA guidelines in malignancy risk stratification of thyroid nodules.

Background: To compare the diagnostic performance in determining the malignancy of thyroid nodules and the fine needle aspiration (FNA) recommendations of the guidelines set forth by the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association in 2020 [2020 Chinese Thyroid Imaging Reporting and Data System (C-TIRADS)], the American College of Radiology in 2017 (2017 ACR-TIRADS) and the American Thyroid Association in 2015 (2015 ATA guidelines). Methods: From January 2021 to December 2021, 1,228 thyroid nodules with definitive postoperative histopathology and ultrasound (US) examination within 3 months before surgery in Shantou Central Hospital were enrolled in this study. We collected the data in 2022. The participants formed a consecutive series. The clinical and US features of the nodules were retrospectively reviewed and categorized according to the 2020 C-TIRADS, the 2017 ACR-TIRADS and the 2015 ATA guidelines. The diagnostic performance and unnecessary FNA rates of the three guidelines were calculated. Results: The 2017 ACR-TIRADS had the highest diagnostic performance [area under the receiver operating characteristic curve (AUROC) 0.938], followed by the 2020 C-TIRADS (AUROC 0.933) and the 2015 ATA guidelines (AUROC 0.928). The ATA guidelines had the highest specificity (93.38%), accuracy (92.10%) and positive predictive value (PPV) (80.56%) among the three guidelines. There were no significant differences in the sensitivity and negative predictive value (NPV) among the three guidelines. The sensitivity, specificity, PPV, NPV and accuracy of the FNA recommendations based on the C-TIRADS were 84.25%, 58.76%, 38.92%, 92.28% and 64.82%, respectively, which were higher than those of the ACR-TIRADS (57.53%, 42.94%, 23.93%, 76.43% and 46.42%, respectively) and the ATA guidelines (62.67%, 13.25%, 18.39%, 53.22% and 25.00%, respectively). Compared with the ACR-TIRADS (76.07%) and the ATA guidelines (81.61%), the C-TIRADS showed advantages in the unnecessary FNA rate (61.08%), especially in nodules larger than 20 mm. Conclusions: The 2020 C-TIRADS, the 2017 ACR-TIRADS and the 2015 ATA guidelines can effectively predict the malignancy risk of thyroid nodules. Compared with the 2017 ACR-TIRADS and the 2015 ATA guidelines, the 2020 C-TIRADS may offer a meaningful reduction in FNA recommendations with the highest efficacy in distinguishing thyroid carcinoma.