Improvement of diagnostic performance of pathologists by reducing the number of pathologists responsible for thyroid fine needle aspiration cytology: An institutional experience

BACKGROUND: Various efforts have been made to improve the diagnostic accuracy of thyroid fine needle aspiration (FNA) cytology. We changed the diagnostic system by reducing the number of pathologists responsible for the thyroid FNA cytology in the routine work, and analyzed the effect on the pathologist's diagnostic performance. METHODS: Since March 1, 2015, 3 pathologists have been responsible for diagnostic thyroid FNA, previously undertaken by 9 equally. We compared the prechange period (three months, 319 nodules) and the postchange period (12 months, 1194 nodules). RESULTS: The turnaround time was shortened from 1.4 ± 0.7 days to 0.9 ± 0.5 days (P < .001). The utilization rate of the Bethesda system for Reporting Thyroid Cytopathology (TBSRTC) increased from 92.5% to 99.8%. Diagnostic rates of categories that are confirmative [II (benign) and VI (malignant)] increased, while the inadequate (I) or indeterminate (III) categories decreased. With category IV (follicular neoplasm), a challenging category in our country, an elevated malignancy rate was found at follow-up. Overall, the diagnostic performance was improved in terms of sensitivity (from 98.5% to 99.2%) and specificity (from 94.4% to 98.4%), with reduced false-negative rates (from 1.5% to 0.8%) and false-positive rates (from 2.9% to 1.1%). The area under the receiver operating characteristic curve increased from 0.861 to 0.958. CONCLUSION: Reducing the number of pathologists responsible for diagnostic thyroid FNA cytology resulted in a higher utilization rate of TBSRTC, and more rapid and accurate diagnosis.