Giblett, Neil1; Sharma, Neil1; Pracy, Paul2
1 Department of Otolaryngology – ENT Specialist Registrar, University Hospitals Birmingham, Birmingham, UK
2 Department of Otolaryngology – Head and Neck Consultant, University Hospitals Birmingham, Birmingham, UK
Background: The ultrasound (U) classification of thyroid nodules, developed by the British Thyroid Association (BTA) was introduced to the 2014 guidelines on the management of thyroid cancer. The recommendation aims to stratify thyroid nodules as benign, suspicious or malignant based on ultrasound appearances termed U1-U5. The aim of this study is to evaluate the accuracy of this grading classification in diagnosing thyroid nodules.
Methods: Retrospective data was collected over a 24-month period between 01/09/14 – 30/08/16 from a tertiary UK centre. All Thyroid ultrasound scans (USS) accompanied by an USS guided diagnostic fine needle aspiration for cytology (FNAC) performed through this date range were initially included. U classification was compared against cytology reports according to the Thy classification and histology results for those cases that later underwent thyroid surgery.
Results: A total of 352 cases were included in this study. 141 (40%) USS guided aspirations in total were nondiagnostic [Thy 1]. A total of 133 [38%] cases underwent thyroid surgery confirming histology. 33 USS reports were deemed benign (U2), 2 (6%) later proving to be malignant on histology. 235 USS were reported as indeterminate (U3), 34 of 84 (40%) histology confirmed cases were malignant. 29 of 42 (69%) suspiciously reported nodules on USS (U4/U5) confirmed malignant histology.
Conclusion: Cytology remains a more accurate measure than USS of the thyroid nodule. There is however a high rate of non-diagnostic cytology results, in this group U classification can be a good predictive marker of suspicion and aid appropriate treatment and decision making.