The Paris System for reporting urinary cytology improves the negative predictive value of high-grade urothelial carcinoma

Impact of the 2022 Paris System on diagnostic accuracy and estimating the risk of high-grade malignancy in urine cytology

In 2016, The Paris System 1.0 (TPS 1.0) was introduced to overcome the problem of lack of a standardized reporting system and leading to diagnostic dilemmas for treating physicians. Following this, TPS 2.0 was introduced in 2022 to deal with certain limitations of TPS 1.0. Objectives of study: To evaluate the diagnostic accuracy and risk of malignancy (ROM) with risk of high-grade malignancy (ROHM) of urinary tract by of TPS 2.0 with TPS 1.0 and conventional reporting (CR) of urine cytology. Data were collected retrospectively from 2016 to 2023 from the departmental archives. The cases were reviewed and categorized as per TPS 2.0, TPS 1.0 and CR. Of 875 urine samples studied, 168 urine samples of patients with histology correlation were analyzed. TPS 2.0 had a maximum sensitivity of 64.2 % in Group A, highest specificity of 95.5, positive predictive value of 96.4 % and negative predictive value of 37.5 % in group B comparison to TPS 1.0 and CR. TPS 2.0 has significantly high sensitivity, and maximum receiver operating curve (ROC) with area under the curve (AUC) score (0.695) compared to TPS 1.0 and CR. TPS 2.0 predicted ROM for AUC, SHGUC and HGUC categories 67.6 %, 92 % and 96.8 %, whereas ROHM 26.5 %, 46.2 %, and 98.8 %, respectively. CR and TPS 1.0 predicted ROHM (95.2 % and 81.5 %), respectively. Implementation of TPS 2.0 revealed highest diagnostic accuracy and ROC AUC score for urinary tract malignancy, compared to TPS 1.0 and CR. Our study results highlight the impact of TPS 2.0 in urine cytology reporting.

Will artificial intelligence (AI) replace cytopathologists: a scoping review of current applications and evidence of A.I. in urine cytology

PURPOSE

Urine cytology, while valuable in facilitating the detection and surveillance of bladder cancer, has notable limitations. The application of artificial intelligence (AI) in urine cytology holds significant promise for improving diagnostic accuracy and efficiency. Our scoping review aims to assess the current evidence of AI's utility in urine cytology.

METHOD

An electronic literature research on the application of AI in the setting of urine cytology was conducted on PubMed, EMBASE, and Scopus from inception to 1st November 2024. Case reports, abstracts, and reviews were excluded from this analysis. Our search strategy retrieved 1356 articles; after excluding 142 duplicates, the remaining 1214 papers were screened by title and abstract. 31 studies entered full-article review, and a total of 16 articles were included in the final analysis.

RESULTS

The main application of AI in urine cytology diagnosis is to automate the identification and characterization of abnormal cells. It has also been utilized for risk stratification of abnormal cells, predicting histologic results from urine cytology samples, and predicting bladder cancer recurrence. Current limitation includes the need for robust training datasets and validation studies to ensure the generalizability of AI algorithms.

CONCLUSION

In summary, AI in urine cytology, though still developing, shows significant promise in enhancing diagnostic accuracy and efficiency. Current evidence suggests that AI, as a valuable tool, could revolutionize urinary tract cancer diagnosis and management.

Evaluation of Diagnostic Accuracy of the Paris System (TPS 2.0) in Urine Cytology Specimens: An Institutional Experience From a Large Cohort of a Tertiary Care Centre

OBJECTIVE

The objective of this study is to evaluate the diagnostic performance of urine cytology using The Paris System (TPS 2.0) in comparison with TPS 1.0, and the Four-Tier Reporting System (FTRS) of our institute for identifying high-grade urothelial carcinoma (HGUC).

METHODOLOGY

A total of 789 urine cytology specimens from 240 patients including 12 UTUC cases with available histological and clinical details were included. Two hundred twenty-two cases were newly diagnosed, whereas 18 were recurrent tumours. Histopathological evaluation categorised the cases as non-neoplastic (33%, 13.7%), low-grade urothelial neoplasms (LGUNs) (94%, 39.2%), high-grade urothelial carcinoma (HGUCs) (110%, 45.8%) and other malignancies (3%, 1.3%).

RESULTS

TPS 2.0 categorised the cases as 14 (5.7%) non-diagnostic or ND/U, 99 (41.5%) NHGUC, 37 (15.4%) AUC, 24 (10%) SHGUC and 66 (27.5%) HGUC. TPS 1.0 had 14 (5.7%) ND/U, 72 (30%) NHGUC, 61 (24.5%) AUC, 3 (1.3%) LGUC, 24 (10%) SHGUC and 66 (27.5%) HGUC. FTRS classified them as 19 (7.5%) ND/UNS, 44 (18.3%) NEG, 88 (36.7%) INC and 89 (37.1%) POS. The ROHM for TPS 2.0 was 71.4% for ND/U, 12.1% for NHGUC, 29.7% for AUC, 79.2% for SHGUC and 89.4% for HGUC. TPS 1.0 showed a similar ROHM for ND/U, SHGUC and HGUC, whereas had 13.8% for NHGUC and 19.7% for AUCs. FTRS, had 78.9% for UNS, 6.8% for NEG, 35.2% for INC and 73.1% for POS. TPS demonstrated a sensitivity of 70.91% and specificity of 90.77% for identifying HGUC, whereas FTRS showed 59.09% sensitivity and 81.54% specificity. Also, TPS was found to be 75% accurate with 62.5% sensitivity and 100% specificity for UTCC cases separately.

CONCLUSION

TPS 2.0 exhibits diagnostic accuracy with better performance in comparison to FTRS, making it a more reliable system for clinical practice. Our findings endorse the utility of TPS 2.0 in improving the accuracy of urine cytology in predicting histological diagnosis of HGUC.

A Comparative Study of the Paris System and Common Reporting System for Urine Cytology With Cyto-Histology Correlation: A Study of 829 Urine Cytology Specimens

BACKGROUND

The Paris System (TPS) diligently detects high-grade urothelial carcinoma (HGUC) and creates a uniform, standardized, reproducible reporting system for urine cytology. However, many centres might still use a common reporting system (CRS). The study aims to compare TPS and CRS for urine cytology with histology correlation.

METHOD

It was a cross-sectional study done from July 2016 to December 2022.

RESULTS

The study included 829 urine cytology samples (96% voided urine) from 478 patients. Histology correlation was available for 138 (16.6%) samples of 115 patients. The frequency of NHGUC, AUC, HGUC and SHGUC was 40.6%, 17.4%, 12.2% and 5.5%, respectively, in TPS. In contrast, in CRS, the frequency of NM, AUS, SM and PM was 69.2%, 13.3%, 4.5% and 13.0%, respectively. TPS and CRS had 64% agreement overall with the kappa test (κ-value 0.479, moderate strength). The agreement between TPS and CRS was 39.8% for NHGUC, 10.97% for AUC and 10.85% for HGUC. After combining a few TPS categories, the agreement increased to 87.7% (κ-value 0.7640, good strength). Histological concordance for AUC, HGUC and NHGUC was 75%, 31.8% and 31.3% in TPS, and it was 50% and 33.3% for AUS and PM, respectively, in CRS. The sensitivity and specificity of TPS and CRS against histology were 37.5% vs. 26.0%, p = 0.0005 and 76.5% vs. 85.3%, p = 0.0083, respectively.

CONCLUSION

TPS and CRS have moderate strength of agreement for urine cytology. TPS was more sensitive than CRS. It may be easy for institutes to transition to a newer TPS system if they still use a CRS.

A review of the performance of urinary cytology with a focus on atypia, upper tract and updates on novel ancillary testing

The Paris System for Reporting Urine Cytology (TPS) is remarkable for its high predictive value in the detection of high-grade urothelial carcinoma, especially of the bladder. However, universal compliance with TPS-recommended threshold for atypical call rates (15%) and TPS performance in the rarer upper tract urothelial carcinomas (UTUC) are challenging. UTUC diagnosis is compounded by instrumentation artifacts, degenerative changes superimposed on an ambiguous cytology, difficult-to-access location, lack of specific standardized criteria, and a limited number of UTUC-focused studies. We reviewed TPS-applied studies published since 2022, noting up to 50%, exceeding the suggested 15% threshold for atypia. Our examination of ancillary tests for UTUC explored novel approaches including DNA methylation analysis, the detection of overexpressed tumor-linked messenger RNAs, and immunohistochemistry on markers such as CK17. Preliminary evidence from our review suggests that ancillary tests display superior performance over cytology, including in voided samples and low-grade urothelial carcinoma. Importantly, voided samples obviate the risks of ureterorenoscopy. Finally, we explored the future opportunities offered by artificial intelligence and machine learning for a more objective application of TPS criteria on urine samples.

Evaluation of a Cytology-Molecular Co-Test in Liquid-Based Cytology-Processed Urine for Defining Indeterminate Categories of the Paris System

INTRODUCTION

Urine cytology using the Paris system (TPS) classification is useful for the detection and monitoring of bladder urothelial carcinoma (UC). However, the categories "atypical urothelial cells" (AUCs) and "suspicious for high-grade urothelial carcinoma" (SHGUC) do not establish a clear diagnosis. This pilot study aimed to investigate whether the presence of mutations in fibroblast growth factor receptor 3 (FGFR3) and telomerase reverse transcriptase (TERT) genes, in urine processed with liquid-based cytology (LBC) could enhance the diagnostic performance of cytology, particularly in defining the indeterminate categories of AUC and SHGUC.

METHODS

Urine samples from 82 UC patients with primary tumors or under surveillance and 10 healthy individuals were examined. The ThinPrep method was used for cytology followed by DNA isolation from urine sediments. Targeted molecular analysis was achieved in 70 cases (63 patients and 7 controls) for exons 7 and 10 of the FGFR3 gene and the TERT gene promoter (pTERT), using PCR and Sanger sequencing. Molecular results were correlated with TPS cytology categories and validated by histopathological findings following cystoscopy.

RESULTS

In healthy subjects, cytology was negative for high-grade urothelial carcinoma (NHGUC) and no mutations were found. No mutations were found in patients with NHGUC cytology, except for one case with equivocal cystoscopy that carried a pTERT mutation. In high-grade urothelial carcinoma cytology (HGUC) (15/20, 75%) of the cases with histologically confirmed UC, molecular analysis revealed the presence of pTERT without FGFR3 mutations. In SHGUC and AUC cytology, FGFR3 and/or pTERT mutations were detected in 3/4 (75%) and 4/4 (100%) histologically confirmed UC cases, respectively. Cytology sensitivity was 85.7% increasing to 100% with the combined cytology-molecular test, whereas specificity remained unchanged at 86.3%.

CONCLUSIONS

This pilot study suggests that the incorporation of FGFR3/pTERT molecular testing in urine LBC could enhance the diagnostic value of cytology by diagnosing bladder urothelial carcinoma in indeterminate cytology categories.

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.

A comparison between conventional and the Paris systems of reporting urinary cytopathology with a literature update

INTRODUCTION

Owing to certain inherent limitations of earlier reporting systems, "The Paris System for Reporting Urinary Cytology (TPS)" was implemented in 2015 to standardize reporting urine cytology with more stringent cytomorphologic criteria. We share our post-TPS experience, comparing it with the conventional system (CS).

AIM

To assess and compare the cyto-histopathologic/cystoscopic agreement between the conventional and the Paris systems (CS and TPS) for reporting urine cytology.

MATERIALS AND METHODS

It is a cross-sectional study involving urine samples from 170 patients divided into two groups (CS and TPS). Of the 170 cases, 85 were reported according to the CS, and 85 were reported according to TPS with all the relevant clinical, radiologic, and cystoscopic findings. Using the kappa statistics, both groups were statistically analyzed for sensitivity, specificity, predictive values, and agreement.

RESULTS

The sensitivity and specificity for high-grade urothelial carcinoma (HGUC) as per TPS were 83.33% and 94.59%, respectively, while they were 73.47% and 80.56% for the conventional system. The agreement for HGUC with TPS was 87.06% with a kappa value of 0.7416, while it was 76.5% with a kappa value of 0.53 for the CS. Implementing the TPS minimized usage of the atypical urothelial cells (AUC) category, increasing the clarity in detecting HGUC.

CONCLUSION

TPS provides better agreement with histopathology than the CS for diagnosing HGUC, which is attributable to stringent TPS criteria that prompt cytopathologists to look more diligently for morphologic and numeric criteria.

Utility of the Paris System in Urine Cytology for Improved Screening of High-Grade Urothelial Carcinoma in Bahrain

BACKGROUND

Urothelial carcinoma, a prevalent and aggressive urological malignancy, necessitates early detection for improved prognosis. Urine cytology serves as a cost-effective screening tool, but inconsistencies in reporting due to the lack of standardized criteria limit its efficacy. The Paris System for reporting urinary cytology (TPS) was introduced to address this issue, aiming to improve diagnostic accuracy. This retrospective study investigates the effectiveness of urine cytology in detecting high-grade urothelial carcinoma (HGUC) using TPS classification, specifically focusing on atypical urothelial cells (AUC) categorized as TPS-III and suspicious for high-grade urothelial carcinoma (SHGUC) categorized as TPS-IV.

METHODS

We reviewed 470 urine cytology samples collected over two years at a tertiary healthcare center in Bahrain. All samples were re-evaluated using TPS classification by two independent consultant cytopathologists blinded to the original cytology report. The analysis included only samples categorized as TPS-III or TPS-IV with corresponding histopathology reports from confirmatory biopsies performed within four months of urine collection. Biopsy results were categorized as either benign/low-grade urothelial carcinoma (non-HGUC) or malignant (HGUC). The positive predictive value (PPV) of urine cytology for HGUC detection was calculated for both TPS-III and TPS-IV categories. Statistical significance was assessed using Fisher's exact test.

RESULTS

Among the 470 urine cytology samples, 40 (8.5%) were classified as TPS-III or TPS-IV. Within this subset, 16 patients underwent confirmatory biopsies. Histopathological analysis revealed HGUC in 12 (75%) patients and non-HGUC (benign or low-grade) in 4 (25%) patients. The PPV of TPS-III for HGUC was 50%, while TPS-IV demonstrated a higher PPV of 90%. However, the difference between these values was not statistically significant (p = 0.25). This study explored the utility of TPS classification in urine cytology for HGUC detection. While SHGUC (TPS-IV) exhibited a numerically higher PPV compared to AUC (TPS-III), the lack of statistical significance necessitates further investigation. Our findings highlight the potential of TPS to improve the accuracy of urine cytology. TPS implementation has been shown to reduce the number of inconclusive "atypical" diagnoses, leading to more targeted investigations.

CONCLUSION

Our study suggests that SHGUC (TPS-IV) within TPS classification framework might hold promise as a more specific indicator for HGUC compared to AUC (TPS-III). However, further research with larger cohorts is necessary to definitively establish the clinical significance of this observation. This investigation paves the way for future studies exploring the potential of TPS, particularly the SHGUC category, as a reliable screening tool for HGUC, potentially leading to earlier diagnoses and improved patient outcomes.

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.

MCM4 expression is associated with high-grade histology, tumor progression and poor prognosis in urothelial carcinoma

BACKGROUND

We previously reported Minichromosome maintenance 4 (MCM4) overexpression in gastric cancer. However, the clinicopathological significance of MCM4 in urothelial carcinoma (UC) has not been investigated. To clarify the clinicopathological significance of MCM4 in UC, we investigated MCM4 expression with immunohistochemistry (IHC).

METHODS

We analyzed the expression and distribution of MCM4 in 124 upper tract urothelial carcinoma (UTUC) samples by IHC. Additionally, using 108 urine samples, we analyzed MCM4 Immunocytochemistry (ICC) expression in urine cytology.

RESULTS

In normal urothelium, MCM4 expression was weak or absent. Meanwhile, the strong nuclear expression of MCM4 was observed in UTUC tissues, and it was detected in 77 (62%) of a total of 124 UTUC cases. MCM4-positive UTUC cases were associated with nodular/flat morphology, high grade, high T stage, and poor prognosis. Moreover, MCM4 expression was significantly higher in the invasive front than in the tumor surface. Similar results were also obtained in TCGA bladder cancer cohort. Additionally, MCM4 expression was associated with high expression of Ki-67, HER2, EGFR, and p53 in UTUC. Among representative cancer-related molecules, MCM4 had an independent predictive value for progression-free survival and high-grade UC. ICC for MCM4 was also performed on urine cytology slides and showed that the nuclear expression of MCM4 was more frequently found in UC cells than in non-neoplastic cells. The diagnostic accuracy of urine cytology was improved by combining MCM4 immunostaining with cytology.

CONCLUSION

These results suggest that MCM4 might be a useful predictive biomarker for high-grade histology, tumor progression and poor prognosis in UC. Moreover, ICC for MCM4 might be helpful for UC detection as additional markers in the cytomorphology-based diagnosis.

Clinicopathological significance of TUBB3 in upper tract urothelial carcinoma and possible application in urine cytology

βIII-Tubulin, encoded by the TUBB3 gene, is a microtubule protein. We previously reported that TUBB3 is overexpressed in renal cell carcinoma. We investigated the clinicopathological significance of TUBB3 in upper tract urothelial carcinoma (UTUC) by immunohistochemistry. In normal tissue, TUBB3 expression was weak or absent. In contrast, TUBB3 overexpression was observed in urothelial carcinoma (UC) tissues in 51 (49%) of 103 UTUC cases. TUBB3 overexpression was associated with nodular/flat morphology, high-grade disease, high T stage, and a poor prognosis. Similar results were obtained in The Cancer Genome Atlas bladder cancer cohort. TUBB3 expression was also associated with high Ki-67 labeling index, CD44v9, HER2, EGFR, and p53 expression in UTUC. Among representative cancer-related molecules, TUBB3 was an independent predictor of progression-free survival and high-grade UC. Finally, using urine cytology samples, we analyzed TUBB3 expression by immunocytochemistry. TUBB3 expression was more frequently found in UC cells than in nonneoplastic cells. The diagnostic accuracy of urine cytology was improved when combined with TUBB3 immunostaining. The findings suggest the importance of TUBB3 in tumor progression and its potential application as a biomarker for high-grade disease and the prognosis of UC. Moreover, combination with TUBB3 immunostaining might improve the diagnostic accuracy of urine cytology.

The Many Faces of Urothelial Carcinomas: An Update From Pathology to Clinical Approach and Challenges in Practice

Urothelial carcinoma is a heterogeneous disease with histomorphological and genomic variations throughout the same tumor or between tumors from different patients. It has been shown that most of these histologic and genetic differences have prognostic significance and may have a guiding role in determining the appropriate treatment choice for the patient. Therefore, it is crucial for both the pathologist and the clinician to be conscious of these variations and to consider them in patient management. Recently, a consensus molecular classification has been developed and categorized urothelial carcinomas into 6 subclasses. These molecular subclasses seem to be associated with prognosis and/or response to certain therapeutic approaches like chemotherapy or immune checkpoint inhibitory therapy; however, it has not yet been sufficiently validated and has some limitations for routine application. As is well known, there are therapeutic limitations in locally advanced or metastatic urothelial carcinomas, especially those inappropriate for standard therapy with platinum-based chemotherapy regimens. Emerging new therapeutic approaches and testing for appropriate patient selection for those are discussed in this article.

Large-scale longitudinal comparison of urine cytological classification systems reveals potential early adoption of The Paris System criteria

INTRODUCTION

Urine cytology is used to screen for urothelial carcinoma in patients with hematuria or risk factors (eg, smoking, industrial dye exposure) and is an essential clinical triage and longitudinal monitoring tool for patients with known bladder cancer. However, urine cytology is semisubjective and thus susceptible to issues including specimen quality, interobserver variability, and "hedging" towards equivocal ("atypical") diagnoses. These factors limit the predictive value of urine cytology and increase reliance on invasive procedures (cystoscopy). The Paris System for Reporting Urine Cytology (TPS) was formulated to provide more quantitative/reproducible endpoints with well-defined criteria for urothelial atypia. TPS is often compared to other assessment techniques to justify its adoption. TPS results in decreased use of the atypical category and better reproducibility. Previous reports comparing diagnoses pre- and post-TPS have not considered temporal differences between diagnoses made under prior systems and TPS. By aggregating across time, studies may underestimate the magnitude of differences between assessment methods.

MATERIALS AND METHODS

We conducted a large-scale longitudinal reassessment of urine cytology using TPS criteria from specimens collected from 2008 to 2018, prior to the mid-2018 adoption of TPS at an academic medical center.

RESULTS

Findings indicate that differences in atypical assignment were largest at the start of the period and these differences progressively decreased towards insignificance just prior to TPS implementation.

CONCLUSIONS

This finding suggests that cytopathologists had begun to utilize the quantitative TPS criteria prior to official adoption, which may more broadly inform adoption strategies, communication, and understanding for evolving classification systems in cytology.