A 20-year and 46,000-specimen journey to Paris reveals the influence of reporting systems and passive peer feedback on pathologist practice patterns

BACKGROUND: An important goal of The Paris System for Reporting Urinary Cytology (TPS) is to reduce unnecessary atypical diagnoses given to urinary tract cytology (UTC) specimens. Since implementation of TPS at the study institution in 2016, the institutional atypical rate has declined only slightly. The authors speculated that TPS might not have had an immediate impact because several faculty members were involved in TPS committees and because TPS contains elements that already had been integrated into institutional practice. To identify factors contributing to alterations in the institutional atypical rate, the authors examined their practice over the last 22 years. METHODS: UTC specimens submitted to the study laboratory between August 11, 1995, and August 10, 2017, were identified. Specimens were linked to the responsible pathologist, specimen diagnosis and type, association with high-grade urothelial carcinoma, and relevant cytomorphologic features. RESULTS: An increase in the institutional atypical rate occurred between 2002 and 2005. The atypical rate among individual pathologists also peaked during this same time. The increase coincided with an increase in the use of UTC and the arrival of a pathologist with a higher rate of atypical diagnoses. A substantial decrease in the institutional atypical rate occurred between 2005 and 2010 and coincided with the creation of the Johns Hopkins Hospital Template, the authors' first standardized reporting system for UTC specimens. CONCLUSIONS: The use of reporting systems (Johns Hopkins Hospital Template and TPS) has coincided with decreases in the institutional atypical rate at the study institution. An individual pathologist may influence the practice patterns of his or her colleagues, resulting in fluctuations in the institutional rate of atypia over time. Cancer Cytopathol 2018;126:381-9.