Urinary tract cytology: a cytologic-histopathologic correlation with The Paris System, an institutional study

INTRODUCTION

Urothelial carcinoma (UC) requires lifelong monitoring, commonly through urinary cytology and cystoscopy. Urine cytology has a relatively high sensitivity for detecting high-grade urothelial carcinoma (HGUC); however, its sensitivity for low-grade urothelial neoplasm (LGUN) is significantly lower with wide interobserver variability. The Paris System (TPS) was proposed to create standardized diagnostic categories with defined cytomorphologic criteria. We attempt to evaluate diagnostic efficacy of identifying UC using TPS through cytologic-histologic correlation.

MATERIALS AND METHODS

A retrospective search identified 170 cases of urine cytology cases with concurrent biopsies collected during a 2-year time period at University of Rochester Medical Center. Patient age, sex, smoking history, prior malignancy diagnoses, cystoscopy findings, specimen collection method, UroVysion results, and 1-year follow-up of surgical pathology cases were included.

RESULTS

Cytologic-histologic correlation was identified in 59% of cases, with 18% true positives and 41% true negatives. Discordant results were identified in 41% of cases; of these, 4% were false positives, 11% false negatives, 12% potential sampling bias, and 14% were low-grade urothelial carcinoma (LGUC). The analysis of this 2-year study finds a positive predictive value of urine cytology for HGUC to be 81%, a negative predictive value of 79%, a sensitivity of 61%, a specificity of 91%, and an accuracy of 79%.

CONCLUSIONS

Our results support TPS's ability to improve the reliability and accuracy of interpretations in urine cytology for HGUC. Nevertheless, additional studies are essential to improve the diagnostic accuracy of LGUN, and urine adequacy, in order to improve patient care and early detection, while identifying potential sampling bias.

Outcome analysis and negative predictive value of the "unsatisfactory/nondiagnostic" category of The Paris System for Reporting Urinary Cytology

INTRODUCTION

The Paris System (TPS) for Reporting Urinary Cytology (UCyto) was published in 2016, but to date, no study addressing the unsatisfactory (UNSAT) category has been published. We aimed to identify the negative predictive value (NPV) for UNSAT UCyto after the implementation of TPS at our institution.

METHOD

For the period from January 1, 2017, to December 31, 2019, we identified all cases with UNSAT diagnosis on UCyto specimens and available cytologic and/or surgical pathology follow-up within 6 months from the UNSAT diagnosis. Cases were deemed true negative (TN) if the follow-up was "negative for high-grade urothelial carcinoma" (NHGUC). Information regarding previous medical history, clinical indications, and specimen type were tabulated and analyzed.

RESULTS

From 6348 UCyto specimens, there were 230 (3.6%) UNSAT diagnoses made on 209 patients (112 [53.6%] men and 97 [46.4%] women) with a median age of 64 years. Of these, 116 UCyto specimens from 106 patients, which had cytologic and/or surgical pathology follow-up within 6 months, were further studied. Most UNSAT UCyto specimens were bladder washing/barbotage (BW/BB), and the most common indication for UCyto was cancer surveillance. The main cause of UNSAT UCyto was low cellularity. There were 5 false-negative (FN) results for high-grade urothelial carcinoma (HGUC), which corresponds to an overall NPV of 84.4%. NPV was highest for patients with UCyto for hematuria, and for patients with BW/BB as UCyto specimen type.

CONCLUSIONS

Our results show that UNSAT diagnoses have a lower NPV than that typical of NHGUC diagnoses, and should be managed accordingly.

A review of urinary cytology in the setting of upper tract urothelial carcinoma

Urothelial carcinomas of the upper urinary tract (UUT) are uncommon. Cytological examination of voided urine or washings from the UUT has been part of the standard workup for upper tract urothelial carcinoma (UTUC); however, its value remains controversial. The lack of uniform terminology and specific diagnostic criteria could also have contributed to the inferior performance of urinary cytology for detecting UTUC. The Paris System for Reporting Urinary Cytology (TPS) has provided a standardized reporting system for urinary cytology specimens with clearly defined cytomorphologic diagnostic criteria and found acceptance on an international level after its implementation in 2016. Recent studies have shown that TPS has led to improved diagnostic performance of urinary cytology; however, most of these studies had focused on the evaluation of lower urinary tract cytology specimens. Only a limited number of new research studies have analyzed the effect of TPS when applied to UUT cytology specimens. In the present report, we have summarized the current understanding and utility of UTUC, including its molecular biology, and reviewed the current literature.