Accuracy of fine-needle aspiration in diagnosing of well-differentiated thyroid cancer at a tertiary care center

Abstract

Background: Thyroid cancer is the third-most common cancer in Saudi females and males. The Bethesda System for Reporting Thyroid Cytopathology provides a diagnostic framework that can be used in surgical decision-making that allows the use of standardized treatment algorithms for each category. The present study aims to assess the accuracy of fine-needle aspiration (FNA) in diagnosing well-differentiated thyroid cancer in comparison to the corresponding final histopathological results. Methodology: This was a retrospective review of 404 patients who underwent FNA cytology, followed by thyroid surgery during 2010–2018. Data were collected from the medical records of these patients. Results: Based on the final histopathological examination results, 63% of the tested nodules were benign and 36% were malignant. The tested thyroid nodules with Bethesda categories II, III, IV, V, and VI were diagnosed as malignant in 8.7% 33.3%, 50%, 60%, and 94.4%, respectively. FNA (Bethesda categories II and VI) for benign and malignant lesions revealed a sensitivity, specificity, positive predictive value (PPV), and negative predictive value of 79.69%, 97.84%, 94.44%, and 91.28%, respectively. Conclusion: FNA is a reliable diagnostic tool for diagnosing thyroid nodules with a high specificity and PPV. The capability of the relatively high overall malignancy rate can be explained by the nature of our institution, being a major regional tertiary and cancer center. The size of the nodule and its location, body mass index, and age had no significant effect on the accuracy of the FNA.