PD50-02 URINE CYTOLOGY DIAGNOSTIC PATTERNS BEFORE AND AFTER IMPLEMENTING THE PARIS SYSTEM FOR REPORTING URINE CYTOLOGY

Abstract

INTRODUCTION AND OBJECTIVE: Management of urothelial carcinoma (UC) is expensive due to a long disease course. Urine cytology is a noninvasive and cost-effective diagnostic and surveillance method in clinical management of UC. The Paris System for Reporting Urine Cytology (TPS) was published in 2016, and introduced more definite diagnostic criteria aimed to improve sensitivity and specificity in detecting high grade UC (HGUC). METHODS: We performed a retrospective review of urine cytology reported in two yrs from Jan. 2013 to Dec. 2014 (prior to TPS, group 1, 7,659 cases), and two yrs from May 2016 to April 2018 (after TPS, group 2, 20,027 cases) to assess the influence of TPS. Time in between was a learning period. We implemented initial grand rounds presentation followed by biweekly urine cytology conferences for difficult cases to practice the utilization of the diagnostic criteria in TPS. The comparison was made between the two groups in diagnostic categories, and UroVysion FISH correlation when available. RESULTS: Urine cytology diagnoses prior to TPS included negative for UC (NUC) 5,294 (69%), atypical urothelial cells (AUC) 2,227 (29%), including mildly atypical (MAUC) 1,437 (18.8%), and suspicious or positive for HGUC (SHGUC/HGUC) 138 (1.8%). Diagnoses after TPS included negative for HGUC (NHGUC/NUC) 18,507 (92.4%), AUC 1,238 (6.2%) (5.3-7.2% among pathologists) (including MAUC 392 cases, 2%), and SHGUC/HGUC 282 (1.4%). Comparing groups 1 and 2 (Table 1), AUC dropped from 29% to 6.2% (p<0.00001), among which MAUC decreased from 18.8% to 2%. All GU pathologists showed significant decrease in AUC (P<0.00001). We reviewed UroVysion FISH results in AUC. Prior to TPS, 980/2,227 (44%) AUC had FISH results and 164 (16.7%) were positive. After TPS, 550/1,238 (44.4%) had FISH results, and 207 (37.6%) were positive (p<0.00001). CONCLUSIONS: Implementing TPS resulted in a significant decrease in atypical diagnoses from 29% to 6.2%. Most noticeably, the MAUC was dramatically decreased from 18.8% to 2%. In addition, after TPS, AUC was significantly better correlated with UroVysion FISH results, which decreased the number of FISH tests and saved medical costs.Source of Funding: N/A