Reclassification of Urinary Cytology according to the Paris System for Reporting Urinary Cytology Correlation with Histological Diagnosis

Introduction: The Paris System for Reporting Urinary Cytology (TPS) was designed to provide precise diagnostic criteria when evaluating urine cytology and standardize the terminology used in reporting. In our study, we have aimed to determine the effect of TPS on the diagnostic performance of urine cytology, its impact on establishing appropriate risk stratification, and its effectiveness in the diagnosis and follow-up of the patients. Methods: We reevaluated 200 liquid-based urine cytologies with available histological diagnoses reported between 2015 and 2021 according to TPS criteria and compared them with the original cytological diagnoses. Area under the curve, sensitivity, specificity, and diagnostic accuracy of both methods were calculated and statistically analyzed to determine the diagnostic performance of the original reporting and TPS. Results: The sensitivity, specificity, positive predictive, negative predictive, and diagnostic accuracy rates of TPS were 60%, 99.3%, 97.2%, 97.2%, 85.7%, and 87.2%, respectively. In TPS, the risk of malignancy for negative for high-grade urothelial carcinoma, atypical urothelial cells, suspicious for high-grade urothelial carcinoma, and high-grade urothelial carcinoma (HGUC) is 3.5%, 20.9%, 60.8%, 97.2%, respectively. In the original reporting, the corresponding risks were 13.4%, 15%, 52%, 100%, respectively. A statistically significant difference was observed between diagnostic criteria of original cytology and TPS (p = 0.001). When the original reporting was compared with the TPS, the discriminative power of TPS in the diagnosis of HGUC was significantly higher (p < 0.001). Conclusions: The use of TPS provided a more accurate risk stratification of patients. The diagnostic performance of urine cytology was improved, especially for HGUC.