Comparison of diagnostic accuracy of conventional method and Bethesda system for reporting thyroid cytopathology in the diagnosis of various lesions of the thyroid: Experience from a tertiary care center of northeastern India

Abstract

Background: Fine-Needle Aspiration Cytology (FNAC) is a valuable, minimally invasive diagnostic tool for discerning benign and malignant thyroid lesions. In the realm of thyroid cytopathology, both the traditional approach and the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) are widely utilized for diagnosing and categorizing these lesions. Aims and Objectives: This study aims to classify thyroid cytology smears using both the conventional method and the Bethesda system and to compare their findings with histopathological diagnoses. Method and Materials: A hospital-based cross-sectional study was conducted over one year, spanning from February 1, 2022, to January 31, 2023. We included 191 cases of FNAC thyroid lesions and categorized them following the guidelines of both the conventional system and the Bethesda system for reporting thyroid cytopathology. Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for both systems were calculated, with histopathology serving as the gold standard for comparison. Furthermore, we calculated the Risk of Malignancy (ROM) for each category within the Bethesda system. Results: The Bethesda system exhibited a notably high sensitivity of 83.33%, surpassing the conventional method's sensitivity of 50%, while both systems shared the same specificity of 90%. The diagnostic accuracy of the Bethesda system, at 89.13%, outperformed that of the conventional method, which stood at 84.78%. Conclusion: This study demonstrates a strong positive correlation with histopathology, indicating high sensitivity, specificity, and accuracy when employing TBSRTC, in contrast to the conventional method.