Accuracy of fine-needle aspiration cytology for detecting cancer in resected thyroid nodules at a referral hospital

Abstract

Background: Thyroid nodules are a common presentation in clinical practice. Fine-needle aspiration cytology (FNAC) is a useful method of triaging patients between benign, suspicious, and malignant categories. Materials and Methods: This is a retrospective review of the electronic medical record of all surgical thyroid patients presenting to our institution between July 2015 and June 2017. The cytological and histological data were reviewed and correlated based on the Bethesda system for reporting thyroid cytopathology. Results: Two hundred and seven patients underwent thyroidectomies during that period of which 164 had preoperative FNAC. The female-male ratio of 4.9:1. On histology, 52% of nodules were benign and 48% of nodules were malignant. When comparing with cytologic diagnosis, FNAC showed a sensitivity of 52%, specificity of 95%, positive predictive value of 92%, negative predictive value of 64%, false positive rate 5%, and false negative rate 48%. Total accuracy was found to be 72%. Conclusion: FNAC is a useful tool in deciding management options for patients, but has limitations, particularly when evaluating follicular lesions. This leads to discrepancy in the calculation of statistical values in literature.