Impact of Implementing the Paris System for Reporting Urinary Cytology: A Single-institutional Experience With Emphasis on Diagnostic Yield of High-grade Urothelial Carcinoma and Low-grade Urothelial Neoplasm.

Abstract

The Paris System (TPS) has recently been proposed as a method to standardize urinary cytology reporting. In this study, we evaluated the impact of implementing TPS compared to the traditional reporting system. In total, 299 urine samples were reclassified according to TPS. We examined correlations between cytological and histological diagnoses, and calculated probabilities for detecting high-grade urothelial carcinoma (HGUC). TPS resulted in a decrease in the proportion of cases diagnosed as atypical urothelial cell (AUC) (43% to 31%). Among the AUC cases, the proportion of histologically confirmed HGUC cases rose (75% to 80%), as did the proportion of low-grade urothelial neoplasms (57% to 71%). All probabilities for detecting HGUC significantly increased using TPS. TPS improved the diagnostic yield of urinary cytology. The implementation of TPS is expected to be a major step towards standardizing urinary cytology reporting and providing clear information to clinicians.