The association between the ultrasonography TIRADS classification system and surgical pathology among indeterminate thyroid nodules.

BACKGROUND: A high proportion of cytologically indeterminate, Afirma-suspicious thyroid nodules are benign. The Thyroid Imaging Reporting and Data System was proposed by the American College of Radiology in 2015 to determine appropriate management of thyroid nodules in a standardized fashion. Our aim was to determine the diagnostic value of the Thyroid Imaging Reporting and Data System in cytologically indeterminate and Afirma-suspicious nodules.

METHODS: We retrospectively queried cytopathology archives for retrospectively for thyroid fine-needle aspiration specimens obtained between February 2012 and September 2016 that were associated with the following: (1) indeterminate diagnosis, (2) ultrasonographic imaging at our institution, (3) an Afirma Gene Expression Classifier-suspicious result, and (4) surgery at our institution. We then calculated the diagnostic value of the Thyroid Imaging Reporting and Data System in predicting surgical pathology.

RESULTS: Our cohort consisted of 133 nodules among 131 patients who underwent thyroid surgery for cytologically indeterminate, Afirma-suspicious nodules. A total of 9 nodules (6.8%) were assigned TR2 "not suspicious," 25 (18.8%) TR3 "mildly suspicious," 81 (60.9%) TR4 "moderately suspicious," and 18 (13.5%) TR5 "highly suspicious." Among our cohort, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the Thyroid Imaging Reporting and Data System was 71.4%, 38.1%, 40.2%, 69.6%, and 50.4%, respectively.

CONCLUSION: Among cytologically indeterminate and Afirma-suspicious nodules, the Thyroid Imaging and Reporting and Data System was a poor predictor of final surgical pathology. Additional prospective studies are needed to validate these findings.