A review of upper urinary tract cytology performance before and after the implementation of The Paris System

European Association of Urology Guidelines on Upper Urinary Tract Urothelial Carcinoma: Summary of the 2025 Update

BACKGROUND AND OBJECTIVE

We present a summary of the 2025 update for the European Association of Urology (EAU) guidelines for upper urinary tract urothelial carcinoma (UTUC). The aim is to provide practical recommendations on the clinical management of UTUC with a focus on diagnosis, treatment, and follow-up.

METHODS

For the 2025 guidelines on UTUC, new and relevant evidence was identified, collated, and appraised via a structured assessment of the literature. Databases searched included Medline, EMBASE, and the Cochrane Libraries. Recommendations within the guidelines were developed by the panel to prioritise clinically important care decisions. The strength of each recommendation was determined according to a balance between desirable and undesirable consequences of alternative management strategies, the quality of the evidence (including the certainty of estimates), and the nature and variability of patient values and preferences.

KEY FINDINGS AND LIMITATIONS

Key recommendations emphasise the importance of thorough diagnosis, treatment, and follow-up for patients with UTUC. The guidelines stress the importance of appropriate treatment taking into account patient values and preferences. Key updates in the 2025 UTUC guidelines include: significant changes to the recommendations for UTUC diagnosis; complete revision of the sections addressing risk stratification, ureteroscopy, and the surgical approach for radical nephroureterectomy; addition of four new recommendations, two related to kidney-sparing management of localised low-risk UTUC and a further two related to management of high-risk nonmetastatic UTUC; a review and adaptation of recommendation for UTUC follow-up; and addition of a new section addressing quality indicators for UTUC management.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This overview of the 2025 EAU guidelines on UTUC offers valuable insights into risk factors, diagnosis, classification, treatment, and follow-up for UTUC. The guidelines contain information on the management of individual patients according to the current best evidence and are designed for effective integration in clinical practice.

The Diagnostic Accuracy of the Paris System for Reporting Upper Urinary Tract Cytology: The Atypical Urothelial Cell Conundrum

BACKGROUND

The diagnosis of upper urinary tract urothelial carcinoma (UTUC) in cytological specimens is challenging, particularly the designation of atypical urothelial cells (AUC). The application of the Paris System for Reporting Urinary Cytology (TPS) has improved the performance of lower tract urothelial carcinoma specimens but has shown variable results in upper tract specimens, which are frequently instrumented.

METHODS

This retrospective study analysed upper tract selective cytology samples from January to December 2023. Samples were classified under TPS 2.0 categories. Histological specimens were used where available as the gold standard to calculate statistical metrics including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Out of 122 samples, 12.2% were considered non-diagnostic or insufficient, with 13.1% designated as Non-high-grade urothelial carcinoma (N-HGUC), 53.3% as atypical urothelial cells (AUC) and 21.3% as positive/suspicious for HGUC. Histopathological correlation was available for 48.7% of cases. The risk of malignancy was: NHGUC (0%), AUC (47%) and HGUC (77.7%). The highest PPV was for HGUC (78%), with a diagnostic accuracy of 81.3% and specificity of 88%. In contrast, AUC had a PPV of 47% in instrumented and non-instrumented samples, rising to 58% in combination with the HGUC category.

CONCLUSION

TPS 2.0 is an effective tool with excellent diagnostic accuracy for HGUC and in excluding malignancies in the N-HGUC category, but in our hands, the high rates of the AUC category, together with the low PPV, remain a major challenge and an obstacle to the correct stratification of patients with UTUC.

Updates on Urothelial Carcinoma of the Upper Urinary Tract with a Focus on Molecular Findings

Urothelial carcinoma (UC) of the upper urinary tract (UUT) is rare, constituting 5% to 10% of UCs, with a higher prevalence in males and older adults. It encompasses various subtypes and, unlike UC of the bladder, often presents as invasive disease. Molecular studies reveal frequent FGFR3 and TP53 mutations, guiding therapeutic strategies. Lynch Syndrome (LS), a hereditary condition, significantly contributes to UUT UC, especially in young patients. Current treatments emphasize platinum-based chemotherapy post-surgery, though immunotherapy shows promise, especially in LS cases. Further molecular insights are crucial for improving diagnosis and treatment.

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.

Implementation of The Paris System for Reporting Urine Cytology improves diagnostic accuracy of selective upper urinary tract cytology

BACKGROUND

The Paris System for Reporting Urine Cytology (TPS) recommends diagnostic criteria for urinary tract cytology, focusing primarily on the detection of high-grade urothelial carcinoma (HGUC) in the lower urinary tract. The second edition of TPS (TPS 2.0), published in 2022, extends these recommendations to the upper urinary tract (UUT); however, there is a lack of comprehensive data on this subject.

METHODS

In total, 223 consecutive UUT cytology specimens from 137 patients were retrieved and reclassified according to TPS 2.0 criteria and were compared with the original diagnosis based on the conventional system (CS). Histologic follow-up within a 3-month period was conducted for 43 patients.

RESULTS

Histologic follow-up revealed 30 HGUCs, five low-grade urothelial carcinomas (LGUCs), and eight nonneoplastic fibrotic tissues. The risk of high-grade malignancy for each TPS diagnostic category was 16.7% for nondiagnostic/unsatisfactory, 2.3% for negative for HGUC (NHGUC), 42.1% for atypical urothelial cells, 50.0% for suspicious for HGUC (SHGUC), and 81.8% for HGUC. In all five cases of histologically diagnosed LGUC, the cytologic diagnosis was NHGUC. When SHGUC/HGUC was considered positive, the diagnostic accuracy of TPS had 63% sensitivity, 95% specificity, a 90% negative predictive value, and a 79% positive predictive value, which were better than those of CS. In addition, the TPS indices did not differ significantly between the specimens obtained before and after the application of contrast reagents.

CONCLUSIONS

TPS implementation improved the accuracy of UUT cytology in predicting histologic HGUC, which was unaffected by the application of contrast reagents. These data indicate the usefulness of TPS for UUT cytology in routine clinical settings.

Urine cytology in the detection of renal cell carcinomas - a territory-wide multi-institutional retrospective review of more than 2 decades

INTRODUCTION

Compared with urothelial lesions of the upper urinary tract, the diagnostic performance of urine cytology in detection of renal cell carcinomas is underreported. This study aims to establish the role of urine cytology in the assessment of renal carcinomas by a multi-institute review of urine cytology from nephrectomy confirmed renal cell carcinomas, referenced against renal urothelial and squamous cell carcinomas.

METHODS

Records of nephrectomy performed from the 1990s to 2020s at three hospitals were retrieved and matched to urine cytology specimens collected within 1 year prior. Patient demographics, specimen descriptors, and histology and staging parameters were reviewed and compared against cytologic diagnoses.

RESULTS

There were 1147 cases of urine cytology matched with renal cell carcinomas, with 666 renal urothelial/squamous carcinomas for comparison. The detection rate for urothelial/squamous (atypia or above [C3+]: 63.1%; suspicious or above [C4+]: 24.0%) were higher than renal cell carcinoma (C3+: 13.1%; C4+: 1.5%) (p < 0.001). The positive rate for upper tract urine exceeded other collection methods at 45.0% (C3+) and 10.0% (C4+) (p < .01). Other factors associated with increased positive rates were male sex, collecting duct carcinoma histology, nuclear grade, and renal/sinus involvement (p < .05). Multivariate analysis revealed additional positive correlations with presence of sarcomatoid tumor cells, lymphovascular invasion, and perinephric fat involvement (p < .05). Larger lesion size and higher urine volume did not improve detection rates (p < .05).

CONCLUSIONS

The detection rate of renal cell carcinomas is suboptimal compared with urothelial carcinomas, although urine samples collected from cystoscopy or percutaneous nephrostomy significantly outperformed voided urine specimens.

Cytologic evaluation of upper urinary tract specimens: An institutional retrospective study using The Paris System for Reporting Urine Cytology second edition with histopathologic follow-up

OBJECTIVE

Cytologic evaluation of the upper urinary tract (UUT) can be challenging due to instrumentation artefacts. This study retrospectively reviewed UUT specimens using The Paris System for Reporting Urinary Cytopathology, second edition (TPS 2.0), compared it with the original reporting system (ORS) and correlated it with histopathologic follow-up.

METHODS

An institutional database was reviewed for the UUT biopsy/resection histopathologic specimens, and we included 52 UUT cytology specimens pertinent to these cases in the study. These specimens were blindly reviewed and reclassified using TPS 2.0. The correlation between TPS 2.0, ORS and histopathologic follow-up was assessed.

RESULTS

The UUT cytology specimens corresponded to 21 (40.4%) high-grade urothelial carcinoma (HGUC), 27 (51.9%) low-grade urothelial carcinoma (LGUC) and 4 (7.7%) benign cases on follow-up. For HGGC cases, the associated TPS categories included unsatisfactory (n = 1, 4.8%), negative for HGUC (NHGUC; n = 3, 14.3%), atypical urothelial cells (AUC; n = 6, 28.6%), suspicious for HGUC (SHGUC; n = 3, 14.3%) and HGUC (n = 8, 38.1%), while ORS categorised the specimens as unsatisfactory (n = 1, 4.8%), negative for malignant cells (NFMC; n = 3, 14.3%), AUC (n = 5, 23.8%), low-grade urothelial carcinoma (LGUC; n = 0, 0%), SHGUC (n = 5, 23.8%) and HGUC (n = 7, 33.3%). The risks of high-grade malignancy among cytologic categories were similar between ORS and TPS (p > 0.05). The majority of LGUC were classified as AUC similarly by ORS and TPS (55.6% vs. 59.3%).

CONCLUSIONS

Our study demonstrated comparable performance between TPS 2.0 and ORS for UUT cytology specimens. Cytological diagnosis of UUT specimens remains challenging, especially for LGUC.

Upper Tract Urothelial Carcinoma: A Narrative Review of Current Surveillance Strategies for Non-Metastatic Disease

Non-metastatic upper urinary tract carcinoma (UTUC) is a comparatively rare condition, typically managed with either kidney-sparing surgery (KSS) or radical nephroureterectomy (RNU). Irrespective of the chosen therapeutic modality, patients with UTUC remain at risk of recurrence in the bladder; in patients treated with KSS, the risk of recurrence is high in the remnant ipsilateral upper tract system but there is a low but existent risk in the contralateral system as well as in the chest and in the abdomen/pelvis. For patients treated with RNU for high-risk UTUC, the risk of recurrence in the chest, abdomen, and pelvis, as well as the contralateral UT, depends on the tumor stage, grade, and nodal status. Hence, implementing a risk-stratified, location-specific follow-up is indicated to ensure timely detection of cancer recurrence. However, there are no data on the type and frequency/schedule of follow-up or on the impact of the recurrence type and site on outcomes; indeed, it is not well known whether imaging-detected asymptomatic recurrences confer a better outcome than recurrences detected due to symptoms/signs. Novel imaging techniques and more precise risk stratification methods based on time-dependent probabilistic events hold significant promise for making a cost-efficient individualized, patient-centered, outcomes-oriented follow-up strategy possible. We show and discuss the follow-up protocols of the major urologic societies.

Learning from the past and present to change the future: Endoscopic management of upper urinary tract urothelial carcinoma

Current guidelines recommend endoscopic management (EM) for patients with low-risk upper urinary tract urothelial carcinoma, as well as those with an imperative indication. However, regardless of the tumor risk, radical nephroureterectomy is still mainly performed worldwide despite the benefits of EM, such as renal function maintenance, no hemodialysis requirement, and treatment cost reduction. This might be explained by the association of EM with a high risk of local recurrence and progression. Furthermore, the need for rigorous patient selection and close surveillance following EM may be relevant. Nevertheless, recent developments in diagnostic modalities, pathological evaluation, surgical devices and techniques, and intracavitary regimens have been reported, which may contribute to improved risk stratification and treatments with superior oncological outcomes. In this review, considering recent advances in endourology and oncology, we propose novel treatment strategies for optimal EM.

The Diagnostic Dilemma of Urothelial Tissue Fragments in Urinary Tract Cytology Specimens

Since the release of The Paris System for Reporting Urinary Cytology (TPS), the assessment of urine cytology specimens has primarily focused on the detection of high-grade urothelial carcinoma (HGUC) and carcinoma in situ (CIS). Fortunately, the malignant cells in these lesions tend to be loosely cohesive, resulting in the natural exfoliation of individual malignant cells into the urine. However, HGUC/CIS lesions occasionally exfoliate larger fragments which can be difficult to assess due to cellular overlap and fragment three-dimensionality. Furthermore, reactive benign urothelial fragments and fragments from low-grade urothelial neoplasms (LGUN) may also be seen in urine specimens and contain atypical cytomorphologic features. As a result, the significance of urothelial tissue fragments (UTFs) is often unclear. Herein, we discuss the literature on UTFs before and after the implementation of TPS, as well as strategies to help overcome this diagnostic challenge.

Diagnostic performance of nuclear matrix protein 22 and urine cytology for bladder cancer: A meta-analysis

PURPOSE

To compare and analyze the diagnostic efficacy of nuclear matrix protein 22 (NMP22) and urine cytology (UC) in the diagnosis of bladder cancer.

METHODS

Search the Chinese and English studies on NMP22 and urinary cytology in the diagnosis of bladder tumors published between 1999 and June, and conduct quality evaluation, data extraction and analysis.

RESULTS

A total of 397 related articles were retrieved, and 12 articles were finally included after screening, including 2456 subjects. The heterogeneity test shows that there is no discernible threshold effect. Perform meta-analysis according to the random effects model. The results showed that the total sensitivity of NMP22 and UC were 0.79 (95% CI [0.73, 0.84]) (CI: Confidence interval), 0.55 (95% CI [0.41, 0.69]), and the total specificity 0.59 (95% CI [0.46], respectively, 0.71), 0.91 (95% CI (0.81, 0.96]), +LR 1.9 (95% CI [1.4, 2.6]) (+LR: positive likelihood ration), 5.9 (95% CI [3.3, 10.6]), -LR 0.35 (-LR: negative likelihood ration), respectively (95% CI [0.27, 0.47]), 0.49 (95% CI [0.38, 0.64]), diagnostic odds ratios 5 (95% CI [3, 9]), 12 (95% CI [7, 21]). The area under the summary receiver operating characteristics curve (AUC) was 0.79 (95% CI [0.75, 0.82]) and 0.81 (95% CI [0.77, 0.84]), respectively.

CONCLUSIONS

NMP22 has moderate diagnostic efficiency for bladder cancer. Its sensitivity is greater than UC, but its specificity is significantly lower than that of UC. At present, it cannot replace traditional cystoscopy and UC, but it can be combined to detect bladder tumors. It plays a major role in screening, postoperative monitoring and follow-up.