One year of experience using the Paris System for Reporting Urinary Cytology

Background: The Paris System for Reporting Urinary Cytology (TPS) was published in November 2015. It focuses on the diagnosis of high-grade urothelial carcinoma (HGUC) and provides criteria with which to define the category of atypical urothelial cells (AUC). The objective of the current study was to compare two 1-year consecutive periods before and after use of TPS.

Methods: A total of 1634 and 1814 urine cytology cases, respectively, were analyzed before and after use of TPS. Histological diagnosis within 6 months was available for 330 and 299 cases, respectively.

Results: After use of TPS, the authors reported significantly fewer low-grade urothelial neoplasms (0.94% vs 1.84%; P<.05) and more cases that were suspicious for HGUC (2.09% vs 0.73%; P<.01) compared with before use of TPS. For the AUC category, there was no significant change in frequency noted for before versus after TPS (6.12% vs 5.18%), whereas the rate of detection of HGUC on histology significantly increased after TPS when compared with before TPS (49.02% vs 28.17%; P<.02). For the HGUC category, neither the frequency (4.69% vs 4.47%) nor the risk of malignancy (89.39% vs 91.04% with HGUC on histology) were found to be significantly different when comparing before and after use of TPS.

Conclusions: In the authors' practice, TPS helped to better characterize the categories of AUC, low-grade urothelial neoplasm, and suspicious for HGUC, which were associated with a higher risk of HGUC compared with the authors' previous classification. Cancer Cytopathol 2018;126:430-6. © 2018 American Cancer Society.