Correlation of ultrasound-based TIRADS and the Bethesda system for reporting of thyroid cytopathology: A study in a tertiary care centre.

Abstract

The age-standardised incidence rate of thyroid cancer in India is 1 in 416 in the general population. This increased incidence has mainly been attributed to improved detection methods for small thyroid lesions. Two such methods are the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TIRADS) and the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). To study the correlation between ACR TIRADS and TBSRTC, and between each system and the final histopathological report. Thyroid cytopathology cases were retrieved for the period January 2019 to July 2022. For each case, the TIRADS score and Bethesda category were noted. Histopathology specimens were also traced. The study comprised 1100 cases, with 955 female and 145 male patients (M:F = 1:6.59), and ages ranging between 7 and 85 years. The TIRADS scoring was available for 1036 cases. Histopathology was available for 231 cases. There was a significant correlation between TIRADS and TBSRTC, with a p-value of 0.000 and a substantial Kappa agreement of 0.688. Both TIRADS and TBSRTC also had significant correlations with the histopathology data, with a p-value of 0.000 for each. The sensitivity values for TBSRTC and TIRADS were 69.4% and 65.8%; specificity, 99.3% and 96.5%; positive predictive value (PPV), 98.3% and 91.8%; and negative predictive value (NPV) 84.7% and 84.4%, respectively. The risk of malignancy (ROM) was also calculated and was found to be high, especially for TBSRTC II, III, IV and V (11.3%, 20%, 61.5%, 97.4% respectively) and TIRADS 2 and 3 (10.3% and 29.6% respectively). The TIRADS and TBSRTC systems of categorisation of thyroid lesions are concordant and could help improve the overall survival rate of patients with thyroid malignancies.