Implementing The Paris System for Reporting Urinary Cytology results in a decrease in the rate of the atypical category and an increase in its prediction of subsequent high-grade urothelial carcinoma

BACKGROUNDIn the current study, the authors evaluated the impact of implementing The Paris System for Reporting Urinary Cytology (PSRUC) on the prevalence of various cytological categories and their association with a subsequent diagnosis of high-grade urothelial carcinoma (HGUC). METHODSA comparative study was conducted over the 6-month period before PSRUC implementation (2013), including 1653 patients and 2371 specimens versus a 6-month period after implementation of the PSRUC (2016), including 1478 patients and 2392 specimens. The following cytological categories were correlated with the subsequent biopsy result when available (355 cases): negative for HGUC (NHGUC), atypical urothelial cells (AUC), suspicious for HGUC, and HGUC. RESULTSAlthough 18.6% of specimens were diagnosed as AUC in 2013, the percentage was 14.4% in 2016 (P<.0001). Concurrently, the prevalence of the benign category increased from 2013 to 2016 (75.4% vs 80%; P<.0001). After implementation of the PSRUC, there was no significant change noted with regard to the association between the categories of NHGUC, suspicious for HGUC, and HGUC and a subsequent HGUC biopsy diagnosis. However, the predictive value of an AUC diagnosis increased from 28.3% to 46.1% (P=.077). Most important, after the implementation of the PSRUC, there was a significant difference noted with regard to the predictive association for HGUC between the NHGUC and AUC groups (13.6% vs 46.1%; P=.003), a difference that was not found to be statistically significant before implementation of the PSRUC (18% vs 28.3%; P=.175). CONCLUSIONSThere was a much higher risk of HGUC conveyed by AUC cytology after implementation of the PSRUC, justifying more aggressive investigations of patients who receive an AUC diagnosis. Cancer Cytopathol 2018;126:207-14. (c) 2017 American Cancer Society.