Background: The ultrasound risk stratification system of the American Thyroid Association (ATA) is frequently adopted in clinical practice. Here, we evaluated its performance in a series of nodules with indeterminate fine-needle aspiration cytology (FNAC) report.
Methods: Indeterminate thyroid nodules diagnosed at 2 medical centers were retrospectively screened, ultrasound images were reevaluated, and lesions were classified according to the ATA. Single ultrasound parameters were also analyzed.
Results: One hundred seventy-three indeterminate lesions were included with 24.8% of malignancy. The high suspicion class showed a cancer rate (75%) significantly (P < .001) higher than that recorded in the other categories (16.8%). Between ultrasound parameters, halo and microcalcifications were the most sensitive and specific ones. The most accurate receiver operating characteristic (ROC)-derived cutoff of nodule's diameter was >4.1 cm. At multivariate analysis, only the ATA class of high suspicion and size >4.1 cm were significantly associated with cancer (odds ratios [ORs] 19.4 and 5.4, respectively).
Conclusion: The ATA ultrasound system is reliable in the risk stratification of indeterminate thyroid lesions.
Keywords: American Thyroid Association (ATA) guidelines; fine-needle aspiration cytology (FNAC); indeterminate; thyroid; ultrasonography.
© 2017 Wiley Periodicals, Inc.