Applying the Paris System for Reporting Urine Cytology Increases the Rate of Atypical Urothelial Cells in Benign Cases: A Need for Patient Management Recommendations

Abstract

The Paris System (TPS) for reporting urinary cytology attempts to unify the terminology in this field. Objectives: To analyze the impact of adopting TPS by measuring nomenclature agreement and cytohistological correlation. Materials and Methods: Voided urine liquid-based cytology samples corresponding to 149 biopsy-proven cases (76 high-grade carcinomas, 40 low-grade carcinomas, and 33 benign lesions), were reclassified by the same pathologist using TPS. Diagnostic agreement and sensitivity for both nomenclature systems was measured. Results: When using TPS, the rate of atypical samples increased 8 times (from 3 to 24.2%) in benign cases, 10 times (from 2.5 to 25%) in low-grade carcinomas, and 2.4 times (from 6.6 to 15.8%) in high-grade carcinomas. The false-positive rate (abnormal cytology in negative or low-grade carcinoma cases) increased from 11 to 34.2%. Sensitivity was higher (63 vs. 49%) with TPS at the expense of a lower specificity (73 vs. 91%). The agreement between both nomenclatures was moderate for negative and high-grade carcinoma cases (k = 0.42 and 0.56, respectively) and weak for low-grade tumors (k = 0.35). Conclusions: Adopting TPS for reporting urine cytology results in a considerable increase in atypical diagnoses, improving sensitivity but lowering specificity. Appropriate management recommendations for patients with an atypical cytological diagnosis are required.

Reclassification of urinary cytology regarding The Paris System for Reporting Urinary Cytology with cytohistological correlation demonstrates high sensitivity for high‐grade urothelial carcinoma

“…Chan et al study also showed TPS criteria improves the value of an AUC diagnosis by lowering the AUC rate and increasing the positive predictive value of AUC diagnosis for high‐grade urothelial carcinoma. However, in the study of Granados et al, there was an increase in the AUC category . In our study, AUC rate was downgraded to 14% (with an initial rate of 52.1%).…”

The Paris system for reporting urinary cytology improves correlation with surgical pathology biopsy diagnoses of the lower urinary tract

“…A Spanish cohort (Granados et al employed up to a six month time frame between 149 voided urine cytology specimens and subsequent surgical biopsies and found that the number of AUC diagnoses increased after reclassification, as opposed to the decrease in the number of AUC diagnoses we observed. While sensitivity also increased in their study, specificity and PPV decreased with use of the TPS . A US cohort evaluating the limitation of degenerative changes in malignant urinary cytology reviewed 112 cases of voided, catheterized or washed urinary cytology specimens within a one year period between cytology and surgical biopsy, and found that application of TPS upgraded about 40% of indeterminate specimens into higher risk categories .…”

The utility of upper urinary tract urine cytology before and after application of the Paris system

“…Some institutions have noted that the most significant change seen from pre to post‐Paris System evaluation lies in the diagnostic rate of the indeterminate category of “atypical” and, to a lesser degree, the “suspicious” category. Although many institutions have displayed a decreased atypical diagnostic rate after implementing TPS diagnostic criteria, few have reported no significant changes in the rate of atypical urine cytology and rare others have reported an increased atypical rate . Of note, many of the studies that showed a decrease in diagnostic rates of “atypical” urine cytology also reported an increased association of these “atypical” cases with subsequent histologic diagnoses of HGUC.…”