The Paris System for reporting urinary cytology in daily practice with emphasis on ancillary testing by multiprobe FISH

Impact of implementing the first edition of the Paris system for reporting: A systematic review and meta-analysis

Urine cytology is a noninvasive, widely used diagnostic tool for screening and surveillance of genitourinary tract neoplasms. However, the absence of unified terminology and clear objective morphological criteria limits the clinical benefit of urine cytology. The Paris System for Reporting Urine Cytology (TPS) was developed with the goal of standardizing reporting and improving urine cytology performance in detecting high-grade malignancy (HGM). We aimed to evaluate potential effects of TPS on improving urine cytology diagnostic performance and clinical utility by conducting a systematic review and meta-analysis. We searched six electronic databases to identify cross-sectional and cohort studies written in English assessing the accuracy of urine cytology in detecting genitourinary tract malignancies of patients under surveillance or with clinical suspicion of malignancy from January 2004 to December 2022. We extracted relevant data from eligible studies to calculate relative distribution of cytology diagnostic categories; ratio of atypical to HGM cytology diagnosis; and risk of HGM (ROHGM) and HGM likelihood ratio (HGM-LR) associated with cytology diagnostic categories. We used a generalized linear mixed model with logit transformation to combine proportions and multilevel mixed-effect logistic regression to pool diagnostic accuracy measurements. We performed meta-regression to evaluate any significant difference between TPS and non-TPS cohorts. We included 64 studies for 99,796 combined total cytology samples, across 31 TPS and 49 non-TPS cohorts. Pooled relative distribution [95% confidence interval (CI)] of negative for high-grade urothelial carcinoma (NHGUC)/negative for malignancy (NM); atypical urothelial cells (AUC); suspicious for high-grade urothelial carcinoma (SHGUC)/suspicious for malignancy (SM); low-grade urothelial neoplasm (LGUN); and HGM categories among satisfactory cytology cases were 83.8% (80.3%-86.9%), 8.0% (6.0%-10.6%), 2.2% (1.4%-3.3%), 0.01% (0.0%-0.1%), and 4.2% (3.2%-5.5%) in TPS versus 80.8% (76.8-2.7%), 11.3% (8.6%-14.7%), 1.8% (1.2%-2.7%), 0.01% (0.0%-0.1%), and 3.3% (2.5%-4.3%) in non-TPS cohorts. Adopting TPS classification resulted in a significant increase in the frequency of NHGUC and a reduction in AUC cytology diagnoses, respectively. The AUC/HGM ratio in TPS cohort was 2.0, which showed a statistically significant difference from the atypical/HGM ratio of 4.1 in non-TPS cohort (p-value: 0.01). Moreover, the summary rate (95% CI) of LGUN called AUC on cytology significantly decreased to 20.8% (14.9%-28.3%) in the TPS compared with 34.1% (26.4%-42.8%) in non-TPS cohorts. The pooled ROHGM (95% CI) was 20.4% (6.2%-50.0%) in nondiagnostic (NDX), 15.5% (9.6%-24.2%) in NHGUC, 40.2% (30.9%-50.2%) in AUC, 80.8% (72.9%-86.8%) in SHGUC, 15.1% (5.7%-34.3%) in LGUN, and 91.4% (87.3%-94.3%) in HGM categories in TPS studies. NHGUC, AUC, SHGUC, and HGM categories were associated with HGM-LR (95% CI) of 0.2 (0.1-0.3), 0.9 (0.6-1.3), 6.9 (2.4-19.9), and 16.8 (8.3-33.8). Our results suggest that TPS 1.0 has reduced the relative frequency of AUC diagnosis, AUC/HGM ratio, and the frequency of LGUNs diagnosed as AUC on cytology. Adopting this classification has improved the clinical utility of SHGUC and HGM cytology diagnoses in ruling in high-grade lesions. However, an NHGUC diagnosis does not reliably rule out the presence of a high-grade lesion.

Real-world performance of Uromonitor® in urothelial bladder cancer detection: a multicentric trial

OBJECTIVES

To compare Uromonitor® (U-Monitor Lda, Porto, Portugal), a multitarget DNA assay that detects mutated proto-oncogenes (telomerase reverse transcriptase [TERT], fibroblast growth factor receptor 3 [FGFR-3], Kirsten rat sarcoma viral oncogene homologue [KRAS]), with urine cytology in the urine-based diagnosis of urothelial carcinoma of the bladder (UCB) within a multicentre real-world setting.

PATIENTS AND METHODS

This multicentre, prospective, double-blind study was conducted across four German urological centres from 2019 to 2024. We evaluated the diagnostic performance of Uromonitor compared to urine cytology in a cohort of patients with UCB and in healthy controls within a real-world setting. Sensitivity, specificity, positive-predictive value (PPV), negative-predictive value (NPV), and accuracy of the tests were measured, in addition to multivariate analyses to assess the ability of individual proto-oncogene mutations in detecting UCB. The biometric sample size was designed to achieve a 10% difference in sensitivity.

RESULTS

Patients with UCB comprised 63.7% (339/532) of the study group. Uromonitor showed a sensitivity, specificity, PPV, NPV, accuracy, and an area-under-the-curve of 49.3%, 93.3%, 92.8%, 51.1%, 65.2%, and 0.713%, respectively. These metrics did not demonstrate statistical superiority over urine cytology in terms of sensitivity (44.6%; P = 0.316). Moreover, the comparison of additional test parameters, as well as the comparison within various sensitivity analyses, yielded no significant disparity between the two urinary tests. Multivariate logistic regression underscored the significant predictive value of a positive Uromonitor for detecting UCB (odds ratio [OR] 9.03; P < 0.001). Furthermore, mutations in TERT and FGFR-3 were independently associated with high odds of UCB detection (OR 13.30 and 7.04, respectively), while KRAS mutations did not exhibit predictive capability.

CONCLUSION

Despite its innovative approach, Uromonitor fell short of confirming the superior results anticipated from previous studies in this real-world setting. The search for an optimal urine-based biomarker for detecting and monitoring UCB remains ongoing. Results from this study highlight the complexity of developing non-invasive diagnostic tools and emphasise the importance of continued research efforts to refine these technologies.

Advances in diagnostic liquid-based cytology

Liquid-based cytology (LBC) has changed the landscape of gynaecological cytology. A growing demand exists for LBC in diagnostic cytology, particularly for ancillary testing, such as immunocytochemistry and molecular testing. Ancillary testing solely based on conventional preparation (CP) methods remains challenging. Recently, the increased demand for specialist testing and minimally invasive techniques, such as endoscopic ultrasonography fine-needle aspiration, to obtain cellular samples has led to an increasing demand for ancillary testing on cytology LBC supernatant, slides and cell block (CB). This facilitates the diagnosis and prognosis in cytology samples enabling personalized treatment. An understanding of the history and future prospects of LBC is crucial for its application in routine diagnostics by cytopathologists and cytotechnologists. In this review, we initiated an internet search using the keyword 'liquid-based cytology', and we conducted a literature review to discuss the usefulness of combined diagnosis of LBC and CP, immunocytochemistry and molecular testing and assessed the quality of nucleic acids in diagnostic LBC. High-quality and cell-rich diagnostic LBC surpassed the CP method alone in terms of reliability and versatility of ancillary testing in cytological diagnosis. Conclusively, diagnostic LBC lends itself to various new technologies and is expected to continue evolving with innovations in the future.

Loss of MTAP Expression by Immunohistochemistry Is a Surrogate Marker for Homozygous 9p21.3 Deletion in Urothelial Carcinoma

Homozygous deletion of the chromosomal region 9p21.3 is common in urothelial carcinoma (UC) and leads to loss of several genes, including CDKN2A and MTAP, resulting in loss of MTAP protein expression. Here, we aimed to explore the diagnostic potential of MTAP immunohistochemistry (IHC) as a surrogate marker for homozygous 9p21.3 deletion (9p21 homozygous deletion [HD]) in UC. MTAP status was determined by IHC on 27 UC tissue specimens with known 9p21.3 status as defined by fluorescence in situ hybridization in matched cytological specimens, by IHC and fluorescence in situ hybridization on a tissue microarray (TMA) containing 359 UC at different stages, and by IHC on 729 consecutive UC from routine practice. Moreover, we analyzed a longitudinal series of matched specimens from 38 patients with MTAP-negative recurrent UC. MTAP loss by IHC was found in all 17 patients with 9p21 HD and in 2/8 cases without 9p21 HD. In the TMA, MTAP loss was more common in metastases (53%) than in muscle-invasive (33%) and non-muscle-invasive UC (29%) (P = .03). In the consecutive series, 164/729 (22%) cases showed loss of MTAP expression. In 41 of these 164 cases (25%), loss of MTAP expression was heterogenous. We also discovered loss of MTAP expression in flat urothelium adjacent to MTAP-negative low-grade UC, suggesting true flat low-grade neoplasia that could not be diagnosed by morphology alone. Longitudinal analysis of recurrences showed persistent negative MTAP status over time in 37/38 (97%) patients. MTAP IHC can serve as a surrogate marker for 9p21 HD in UC and as a diagnostic tool to differentiate reactive urothelium from urothelial neoplasia. It also provides a unique opportunity to study clinicopathological associations and the heterogeneity of 9p21 HD across the whole spectrum of UC manifestations.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 1: Comparison of Bladder Cancer Grading System Performance

Grade is a key prognostic factor in determining progression in nonmuscle invasive papillary urothelial carcinomas. The 2 most common grading methods in use worldwide are the World Health Organization (WHO) 2004 and 1973 schemes. The International Society of Urological Pathology (ISUP) organized the 2022 consensus conference in Basel, Switzerland on current issues in bladder cancer and tasked working group 1 to make recommendations for future iterations of bladder cancer grading. For this purpose, the ISUP developed in collaboration with the European Association of Urology a 10-question survey for their memberships to understand the current use of grading schemes by pathologists and urologists and to ascertain the areas of potential improvements. An additional survey was circulated to the ISUP membership for their opinion on interobserver variability in grading, reporting of urine cytology, and challenges encountered in grade assignment. Comprehensive literature reviews were performed on bladder cancer grading prognosis and interobserver variability along with The Paris System for urine cytology. There are notable differences in practice patterns between North American and European pathologists in terms of used grading scheme and diagnosis of papillary urothelial neoplasm of low malignant potential. Areas of common ground include difficulty in grade assignment, a desire to improve grading criteria, and a move towards subclassifying high-grade urothelial carcinomas. The surveys and in-person voting demonstrated a strong preference to refine current grading into a 3-tier scheme with the division of WHO 2004 high grade into clinically relevant categories. More variable opinions were voiced regarding the use of papillary urothelial carcinoma with low malignant potential.

The Paris system classification for urinary cytology in patients under bacillus Calmette-Guerin treatment

BACKGROUND

The role of urinary cytology as a diagnostic test for the detection and surveillance of urothelial cancer is crucial. Intravesical bacillus Calmette-Guerin (BCG) is the appropriate therapeutic strategy for patients with high-grade urothelial carcinoma (HGCU) or in situ carcinoma. We investigate how applicable is the Paris System for reporting urinary cytology (TPS) and how accurate is urinary cytology, in patients who undergo intravesical BCG instillations.

METHODS

Our study contains urine samples from patients during the period January 1, 2017 to December 31, 2019. The inclusion criteria were patients with history of urothelial bladder carcinoma who had been treated with intravesical BCG instillation and cytology was followed by histology. We report our results and estimate the risk of high-grade malignancy (ROHM) for each TPS category and cytology accuracy.

RESULTS

Four hundred thirty-eight samples corresponding to 146 patients fulfilled the criteria to be included in the study. There were 2 inadequate, 118 negative for high-grade urothelial carcinoma (NHGUC), 14 atypical urothelial cells (AUC), 6 suspicious for high-grade urothelial carcinoma (SHGUC), and 6 cases HGUC. Corresponding histology assessment has shown that the ROHM amounted to 0 for inadequate, 3.4% for NHGUC, 57% for AUC, 100% for SHGUC and HGUC. Sensitivity was 50%, specificity 100%, PPV 100%, NPV 91%, and accuracy 91.7%, considering inadequate, NHGUC and AUC as negative and SHGUC and HGUC as positive result. However, considering AUC a positive result, the accuracy parameters were different; sensitivity 83.3%, specificity 95%, PPV 76.9%, NPV 96.67%, and accuracy 93%.

CONCLUSION

The Paris system for reporting urinary cytology can be safely applied to patients during follow-up after BCG intravesical administration.

Diagnostische und prädiktive Marker in der Harntraktzytologie

In der Routinediagnostik spielt die Mehrfach-Fluoreszenz-in-situ-Hybridisierung (FISH) nach wie vor die führende Rolle in der Abklärung unklarer Atypien in der Harntraktzytologie. Die Paris-Klassifikation (The Paris System, TPS) bildet eine wichtige Grundlage zur gezielten Indikationsstellung der FISH und untermauert die Bedeutung der morphologischen Korrelation für eine integrative Diagnosestellung. Die Next-Generation-Sequencing-Technologie, welche durch gleichzeitigen Nachweis multipler genetischer Alterationen eine hohe Sensitivität erzielt, wird in naher Zukunft auch in der Harntraktzytologie Anwendung finden.

The Paris System for Reporting Urinary Cytology: A Meta-Analysis

The Paris System (TPS) for Reporting Urinary Cytology is a standardized, evidence-based reporting system, comprising seven diagnostic categories: nondiagnostic, negative for high-grade urothelial carcinoma (NHGUC), atypical urothelial cells (AUC), suspicious for high-grade urothelial carcinoma (SHGUC), HGUC, low-grade urothelial neoplasm (LGUN), and other malignancies. This study aimed to calculate the pooled risk of high-grade malignancy (ROHM) of each category and demonstrate the diagnostic accuracy of urine cytology reported with TPS. Four databases (PubMed, Embase, Scopus, Web of Science) were searched. Specific inclusion and exclusion criteria were applied, while data were extracted and analyzed both qualitatively and quantitatively. The pooled ROHM was 17.70% for the nondiagnostic category (95% CI, 0.0650; 0.3997), 13.04% for the NHGUC (95% CI, 0.0932; 0.1796), 38.65% for the AUC (95% CI, 0.3042; 0.4759), 12.45% for the LGUN (95% CI, 0.0431; 0.3101), 76.89 for the SHGUC (95% CI, 0.7063; 0.8216), and 91.79% for the HGUC and other malignancies (95% CI, 0.8722; 0.9482). A summary ROC curve was created and the Area Under the Curve (AUC) was 0.849, while the pooled sensitivity was 0.669 (95% CI, 0.589; 0.741) and false-positive rate was 0.101 (95% CI, 0.063; 0.158). In addition, the pooled DOR of the included studies was 21.258 (95% CI, 14.336; 31.522). TPS assigns each sample into a diagnostic category linked with a specific ROHM, guiding clinical management.

Indeterminate atypia in urinary tract cytology: Does it really matter?

The study of atypia in urinary cytology has been ongoing for decades but most studies have focused primarily on test performance in patients with concurrent biopsies and/or limited follow-up periods. While these data are useful, many studies fail to consider patient factors that may alter the pretest probability, which can subsequently affect test performance. An isolated diagnosis of malignancy in urinary cytology usually has a high positive predictive value and allows a urologist to conduct a rigorous workup of the patient to establish a tissue diagnosis. However, it is less certain how an atypical diagnosis impacts patient care, given that many patients have a history of bladder cancer and are already under surveillance with cystoscopy at regular screening intervals. Furthermore, a discrete negative urine cytology is unlikely to allow a patient to forego a cystoscopy procedure due to limitations in the sensitivity of urine cytology. Over the last several years, the introduction of The Paris System for Reporting Urinary Cytology (TPS) has improved the predictive value of atypical diagnoses, but additional studies are needed to evaluate the performance of these diagnoses in specific clinical situations. Such data could better inform urologists on how to manage patients with atypical diagnoses. This review discussed the diagnosis of atypia in urinary cytology and the impact of such a diagnosis in various clinical contexts.

Keratin 17 Is a Novel Cytologic Biomarker for Urothelial Carcinoma Diagnosis

OBJECTIVES

The microscopic features of urine cytology specimens are subjective and may not reliably distinguish between benign urothelial cells and low-grade urothelial carcinoma (UC). Prior studies demonstrated that keratin 17 (K17) detection in biopsies is highly sensitive for UC. The current study aimed to define K17 diagnostic test performance for initial screening and detect recurrent UC in urine specimens.

METHODS

K17 was detected by immunocytochemistry (ICC) in consecutively collected urine specimens (2018-2019). A qualitative score for the K17 test was determined in 81 samples (discovery cohort) and validated in 98 samples (validation cohort). K17 sensitivity and specificity were analyzed in both cohorts across all grades of UC.

RESULTS

Based on the discovery cohort, the presence of 5 or more K17 immunoreactive urothelial cells (area under the curve = 0.90; P < .001) was the optimal threshold to define a K17-positive test. The sensitivity of the K17 ICC test for biopsy-confirmed UC was 35 of 36 (97%) and 18 of 21 (86%) in the discovery and validation cohorts, respectively. K17 was positive in 16 of 19 (84%) specimens with biopsy-confirmed low-grade UC and in 34 of 34 (100%) of specimens with high-grade UC.

CONCLUSIONS

K17 ICC is a highly sensitive diagnostic test for initial screening and detection of recurrence across all grades of UC.

"Indeterminate" UroVysion Fluorescence In Situ Hybridization Results

OBJECTIVES

UroVysion cases with one to three abnormal cells that do not meet the threshold for positivity may be better classified as "indeterminate." The aim of this study is to determine the incidence and clinical significance of these indeterminate UroVysion results.

METHODS

The UroVysion fluorescence in situ hybridization (FISH) results over a 4-year period in our institution were retrospectively analyzed. Follow-up of the initial UroVysion cases, including urine cytology or bladder biopsy performed within 12 months of the initial diagnosis of the result, was obtained from pathology reports.

RESULTS

A significant fraction (178 of 1,907, 9.3%) of the UroVysion cases had indeterminate results. Overall, the subsequent malignancy rate of the group with indeterminate UroVysion results (14 of 59, 23.7%) was higher than the group with normal results (48 of 319, 15.0%), although the difference was not significant (P = .124). For patients without a history of urinary tract neoplasm, the subsequent malignancy rate in the group with indeterminate results (7 of 18, 38.9%) was significantly higher than the group with normal results (16 of 103, 15.5%) (P = .044).

CONCLUSIONS

Our results support that indeterminate UroVysion FISH result may warrant closer clinical follow-up in patients without a history of urinary tract neoplasm. We suggest reporting these cases as "aneusomy of undetermined significance."

A 25-year perspective on advances in an understanding of the biology, evaluation, treatment and future directions/challenges of urothelial cancer

The Urologic Oncology Journal was founded 25 years ago and we reviewed the literature since that time in the area of urothelial cancer to see the progress and pitfalls we have made over this time period. A comprehensive literature search was conducted by the authors involved who are all actively involved in research, clinical trials, and treatment for urothelial cancer and the results were summarized over the past 25 years. The field of urothelial cancer has evolved tremendously in the last 25 years with the incorporation of molecular subtyping, novel imaging, immunotherapy, and robotic surgery. However, treatments such as BCG and radical cystectomy have remained steadfast over the last 25 years. Although we have a better understanding of the biology of bladder cancer, we still have a long way from being able to cure patients with bladder cancer and eliminate morbidity from treatments. Nevertheless, considerable progress has been made since the founding of the Urologic Oncology Journal 25 years ago.

Experience on the use of The Paris System for Reporting Urinary Cytopathology: review of the published literature

INTRODUCTION

The Paris System for Reporting Urinary Cytology (TPS) was first published in 2016 with clear objectives to standardize cytologic diagnostic criteria and provide uniform reporting, in order to improve patient stratification and associated clinical management. The aim of this paper is to evaluate the performance of TPS and review the literature published since TPS was introduced.

MATERIALS AND METHODS

Original articles focusing on the utilization and performance of TPS in urinary cytology specimens were identified using PubMed for publications from January 2016 to July 2020, using the keywords "Paris System", "urine cytology", and "urinary cytology".

RESULTS

Twenty-three relevant articles in the literature regarding the use of TPS were included in the review from a total of 30,802 urine cytology specimens, of which 21,485 (69.8%) had available diagnoses. Distribution of cases among categories ranged from 50.5% to 95.3% for negative for high-grade urothelial carcinoma (NHGUC), 1.2% to 23% for atypical urothelial cells (AUC), 0.2% to 6.6% for suspicious for high-grade urothelial carcinomas (SHGUC), and 2.2% to 14.1% for high-grade urothelial carcinomas (HGUC). The calculated risk of high-grade malignancy (ROHM) ranged from 8.7% to 36.8% for NHGUC, 12.3% to 60.9%% for AUC, 33.3% to 100% for SHGUC, and 58.8% to 100% for HGUC. Mean ROHM weighted by sample size was calculated at 15.7% (±7.8%), 38.5% (±14.3%), 76.2% (±17.2%), and 88.8% (±12.7%) for NHGUC, AUC, SHGUC, and HGUC, respectively. Reported sensitivity of TPS ranged from 40% to 84.7%, specificity from 73% to 100%, PPV from 62.3% to 100%, and NPV from 46% to 90%.

CONCLUSIONS

The application of TPS in the selected series has improved the screening and surveillance potential of urine cytology, while reducing high rates of indeterminate diagnoses, improving sensitivity and providing proper risk stratification for patients.

Significant reduction of indeterminate (atypical) diagnosis after implementation of The Paris System for Reporting Urinary Cytology: A single-institution study of more than 27,000 cases

BACKGROUND

Urinary cytology is a noninvasive and cost-effective diagnostic and surveillance test in the clinical management of urothelial carcinoma (UC). The Paris System for Reporting Urinary Cytology (TPS), published in 2016, introduced definite diagnostic criteria aimed at improving performance in detecting high-grade UC (HGUC) and decreasing the indeterminate (atypical) diagnosis.

METHODS

The authors retrospectively reviewed and compared urinary cytology diagnoses reported between January 2013 and December 2014 (pre-TPS, 7658 cases) and between May 2016 and April 2018 (post-TPS, 20,026 cases) to assess the influence of TPS in their practice. The time in between was used as a learning period. Follow-up information and correlation with the UroVysion fluorescence in situ hybridization test were obtained when available.

RESULTS

Urinary cytology diagnoses pre-TPS included negative for UC (NUC) (n = 5293; 69.2%), atypical urothelial cells (AUC) (n = 2227; 29%), and suspicious/positive for HGUC (SHGUC/HGUC) (n = 138; 1.8%). Diagnoses post-TPS included negative for HGUC (NHGUC) (n = 18,507; 92.4%), AUC (n = 1237; 6.2%), and SHGUC/HGUC (n = 282; 1.4%). Comparing the pre-TPS and post-TPS periods, AUC diagnoses decreased from 29% to 6.2% (P < .00001), and the specificity and positive predictive value of AUC to detect HGUC significantly improved from 49% to 86% (P < .00001) and from 9% to 39% (P = .002), respectively. The correlation of an AUC diagnosis with a positive UroVysion test improved from 17% to 38% (P < .00001), whereas overall use of the UroVysion test was decreased.

CONCLUSIONS

Implementation of TPS resulted in a significant reduction in AUC diagnoses that had a superior correlation with a subsequent biopsy and a UroVysion test, resulting in potential reductions in test use and medical cost.