The Efficacy of Bethesda System for Prediction of Thyroid Malignancies- A ۹ Year Experience from a Tertiary Center

Introduction: The best initial investigation for thyroid nodule is fine needle aspiration (FNA). Bethesda System is an international standardized system of reporting thyroid nodules and recommends subsequent management. Every institution should assess the risk of malignancy in each category to avoid unnecessary thyroid surgeries, with this aim we conducted a review at our center to calculate risk of malignancy in each category.   Materials and Methods: Retrospective ۹-year (۲۰۰۹–۲۰۱۸) review of thyroid FNAs done at a tertiary care Centre. The FNA was stratified according to The Bethesda System. Histopathology reports of the operated cases were used to evaluate the cytology for diagnostic accuracy.   Results: There were ۴۹۵ patients who underwent thyroidectomy. The mean age of the cohort was ۴۲.۵۱ +/- ۱۳.۲ years and ۳۸۷ (۷۸.۲%) were females. The frequency of Bethesda categories I, II, III, IV, V, and VI were ۹.۱%, ۵۵.۶%, ۱۶.۴%, ۶.۵%, ۹.۳%, and ۳.۲% respectively. Malignancy rate in operated thyroid nodules were ۳۷.۸%, ۸.۴%, ۳۳.۳%, ۵۰.۰%, ۸۹.۱%, and ۱۰۰% for Bethesda categories I to VI, respectively. The sensitivity, specificity, negative predictive value and positive predictive value and their ۹۵% CIs were calculated as ۸۱.۳۰ (۷۳.۲۸ – ۸۷.۷۶%), ۷۷.۰۶ (۷۲.۱۲ – ۸۱.۵۱%), ۹۱.۶۴ (۸۸.۳ – ۹۴.۱%) and ۵۷.۱۴ (۵۱.۷۹ – ۶۲.۳۳%). The overall diagnostic accuracy was ۷۸.۲۲ (۷۴.۱۲ – ۸۱.۹۵%).   Conclusions: All the Bethesda categories showed greater malignancy risks than other reported studies. Knowledge of local rates of malignancy is important to accurately predict the risk of malignancy even when reported with internationally accepted nomenclature like the Bethesda System.

کلیدواژه ها:

Bethesda ، Fine needle aspiration ، malignancy risk ، Thyroid nodule