Urine exosomes as biomarkers in bladder cancer diagnosis and prognosis: From functional roles to clinical significance

Bladder cancer is one of the top ten most common cancers and top ten causes of cancer death globally. 5-year survival rates have decreased in Australia from 66% to 55% in the past three decades. The current gold standard for diagnosis is cystoscopy. However, cystoscopies are an invasive and health-resource intensive procedure which has sub-optimal sensitivity for flat lesions such as CIS (carcinoma in situ) and low specificity for differentiating inflammation from cancer - hence requiring biopsies under anesthesia. Frequent and life-long surveillance cystoscopy is required for most patients since there are high rates of progression and local recurrence in high-risk non-muscle invasive cancer (NMIBC) as well as poor outcomes associated with delayed detection of muscle-invasive bladder cancer (MIBC). There is an unmet need for a non-invasive test to provide better discrimination and risk-stratification of bladder cancer which could aid clinicians by improving patient selection for cystoscopy; enhanced risk stratification methods may guide the frequency of surveillance cystoscopies and inform treatment choices. Exosomes, which are nano-sized extracellular vesicles containing genetic material and proteins, have been shown to have functional roles in the development and progression of bladder cancer. Exosomes have also been demonstrated to be a robust source of potential biomarkers for bladder cancer diagnosis and prognosis and may also have roles as therapeutic agents. In this review, we summarize the latest evidence of biological roles of exosomes in bladder cancer and highlight their clinical significance in bladder cancer diagnosis, surveillance and treatment.

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.

High-grade urothelial carcinoma with hypochromatic chromatin in urine cytology

INTRODUCTION

Some high-grade urothelial carcinomas (UCs) in urine cytology have hypochromatic chromatin, but the incidence and criteria for diagnosis are not well described.

MATERIALS AND METHODS

Urine cytology cases with biopsy follow up were reviewed.

RESULTS

Cytospin preparations from 331 cases with biopsy follow up (230 benign/low-grade UC, 101 malignant) were reviewed. There were no false-positive cases. Cases with malignant cells with hypochromatic chromatin were identified in a total of 17 cases (16.8% of all malignancies). These comprised 2 carcinoma in situ, 11 high-grade papillary UC, 3 invasive UC, and 1 adenocarcinoma. Sixteen of 93 high-grade UCs (17.2%) had cells with hypochromatic chromatin. These cells were the only type of malignant cell in 4 of 101 cases (4.0%). All cases had cells with high nuclear-to-cytoplasmic ratios and markedly indented and irregular nuclear membranes that could be identified on both cytology and subsequent histology.

CONCLUSIONS

Malignant urothelial cells in urine cytology with hypochromatic chromatin can be present in 17% of cases and can be diagnosed as "positive for malignancy" based on their high nuclear-to-cytoplasmic ratio, and markedly indented and irregular nuclear membranes.

Should "suspicious for high-grade urothelial carcinoma" and "positive for high-grade urothelial carcinoma" remain separate categories?

BACKGROUND

The Paris System (TPS) for Reporting Urinary Cytology aims to standardize urine cytology reporting. Per TPS, the diagnosis of "suspicious for high-grade urothelial carcinoma (SHGUC)" is applied in cases that have few urothelial cells with severe atypia but are quantitatively insufficient for a diagnosis of "high-grade urothelial carcinoma (HGUC)." In our study, we compared the diagnostic accuracy and risk of malignancy (ROM) of these 2 categories to assess whether they could be combined in clinical practice to perhaps improve overall interobserver variability.

METHODS

All urine specimens with a diagnosis of either SHGUC or HGUC from January 2016 to July 2019 were retrieved from the pathology database of 2 large academic institutions. Only cases with follow-up biopsies within 6 months were included.

RESULTS

One hundred eighty-nine cases met the study criteria. Of these, 122 had a cytologic diagnosis of SHGUC, and 67 had a diagnosis of HGUC. Ninety-five (78%) cases from the SHGUC group and 64 (96%) cases from the HGUC group had biopsy-proven HGUC. The majority of cases with discordance had a history of treatment with either intravesical bacillus Calmette-Guérin or mitomycin. The difference in the rate of biopsy-proven HGUC between the SHGUC category and the HGUC category (95/122 vs 64/67, respectively) was statistically significant (P < .001).

CONCLUSIONS

The difference in ROM between SHGUC and HGUC was statistically significant in our study cohort. Intravesical chemotherapy was frequently observed in negative biopsy cases in both groups. Our preliminary findings suggest that the 2 TPS categories should remain separate.

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.

Cell blocks in urine cytopathology: do they add value to the diagnosis? A pilot study

INTRODUCTION

The utility of cell block (CB) preparation is well established in cytopathology. Despite 23.3% of College of American Pathologists-accredited laboratories using CB with liquid-based preparations on urine cytology (UC) cases, there are very few studies on their performance. To determine their usefulness, we conducted a retrospective review of UC cases that received CB.

MATERIALS AND METHODS

We identified 27 UC cases with ThinPrep (TP) and CB preparation between 2016 and 2020 at our institution. Clinical history and follow-up data were compiled. A blinded review of TP alone, and TP together with CB, was performed by 2 pathologists and 2 cytotechnologists. Diagnoses were rendered in accordance with The Paris System for Reporting Urine Cytology.

RESULTS

Blood and acute inflammation were common background elements in cases that received CB preparation. In total, CB upgraded the diagnosis in 7 of 27 cases (26%). The maximum utility of CB preparation was seen in indeterminate cases where 60% (6 of 10) were upgraded, including 71% (5 of 7) of atypical urothelial cells (AUC) and 30% (1 of 3) of suspicious for high-grade urothelial carcinoma (HGUC). One case (1 of 12, 8%) diagnosed as negative for HGUC on TP was diagnosed as low-grade urothelial neoplasia on CB.

CONCLUSIONS

Our results demonstrate that adjunct use of CB preparation aids in a definitive diagnosis on AUC category and may be helpful in cases with cell clusters or tissue fragments, or cases suspicious for HGUC. Further correlation studies are warranted in this area to expand our knowledge about the utility of CBs in urine cytology.

The predictive value of positive and suspicious urine cytology: Are they different?

BACKGROUND

Urine cytology evaluation is an effective test in the detection of high-grade urothelial carcinoma (HGUC). While the guideline distinguishes the 2 categories: "positive for HGUC" (PHGUC) and "suspicious for HGUC" (SHGUC), the association between these categories with their subsequent follow-up biopsies remains unclear. This study aims to determine and compare the positive predictive value (PPV) of the specimens in PHGUC and SHGUC categories with their respective histologic diagnoses.

METHODS

During the period of 03/01/2008 to 07/31/2018, urine cytology cases diagnosed as PHGUC and SHGUC with subsequent bladder biopsy within 12 months were retrieved. All cases were correlated with first biopsy obtained during 12 months of cytology specimen. Biopsy result with HGUC, carcinoma in situ, or non-urothelial carcinoma diagnoses were considered as concordance.

RESULTS

378 cases (229 SHGUC and 149 PHGUC) were identified from 263 patients. For the 229 SHGUC cases, the PPV was 72% (n = 166) and for the 149 PHGUC cases, the PPV was 85% (n = 127). While both categories have high PPV, they are statistically significant (p < 0.0001). Additionally, 33 cases were found to have low-grade urothelial carcinoma (LGUC), constituting a portion of discordant results.

CONCLUSION

PHGUC and SHGUC categories are both associated with a high risk of malignancy, however, there is a statistically significant difference between them in our study, supporting the PSRUC guidelines of two separate categories. In instances when urine cytology is discordant with biopsy results, further investigation and clinical follow up is warranted. LGUC appears to remain a common pitfall especially in the suspicious category.

Methylation study of the Paris system for reporting urinary (TPS) categories

AIMS

Bladder EpiCheck is one of several urinary tests studied to identify bladder tumours and analyses 15 methylation biomarkers determining bladder cancer presence on the basis of methylation profile.

METHODS

374 patients diagnosed with high-grade non-muscle invasive bladder cancer were treated and followed for 1 year with voided urine cytology and white-light cystoscopy and biopsies according to European Association of Urology Guidelines. 268 cases were diagnosed with high-grade papillary carcinoma, while 106 cases were carcinoma in situ. Bladder EpiCheck test was performed together with cytology in all cases.

RESULTS

Comparing cytological categories of negative for high-grade urothelial carcinoma (NHGUC) and atypical urothelial cells (AUCs), we found that an EpiScore <60 correlates with NHGUC (p=0.0003, Fisher's exact test), while comparing AUC and suspicious for high-grade urothelial carcinoma (SHGUC) or SHGUC and high-grade urothelial carcinoma (HGUC) categories, an EpiScore ≥60 correlates with SHGUC and HGUC, respectively (p=0.0031 and p=0.0027, Fisher's exact test). In each TPS category, we found that sensitivity, specificity, Positive Predicitve Value (PPV) and Negative Predictive Value (NPV) of the Bladder EpiCheck test in HGUC category were higher than those observed in SHGUC group (sensitivity=98%, specificity=100%, NPV=85.7%, PPV=100% vs sensitivity=86.6%, specificity=52.3%, NPV=84.6%, PPV=56.5%).

CONCLUSIONS

Analysing methylation study results, we demonstrated that different TPS cytological categories also carry a distinct molecular signature. Moreover, our results confirm that cytological categories SHGUC and HGUC are different entities also from a molecular point of view and should continue to represent distinct groups in TPS.

Immunocytochemical expression of Ki-67/p16 in normal, atypical, and neoplastic cells in urine cytology using BD SurePath™ as preparation method

Objective:

The objective of this study was to investigate the expression of Ki-67/p16 in urothelial cells in cytological material.

Materials and Methods:

There were 142 urines including normal controls, anonymous rest urine, controls after treatment for urothelial carcinoma (UC) and newly diagnosed UC. Immunocytochemistry for ki-67/p16 dual staining kit was performed on all specimens.

Results:

Eight high-grade UC and six anonymous specimens showed dual positivity. None of the low-grade UC or the control specimens after treated UC showed dual staining. Fifteen of 84 (17.8%) symptomatic cases were negative for both markers, and 59/84 (70.2%) showed positivity for both but not dual staining. Twenty-seven of 84 cases were positive for either Ki-67 (n = 22) or p16 (n = 5). Normal controls and benign specimens were negative for p16.

Conclusions:

Co-expression of p16/Ki-67 in the same cells was found in 16.6% of the cases. All were high grade, and co-expression seems to have limited practical impact as an additional marker in urine cytology. Any positivity for p16 alone strongly indicates malignancy. Negative p16 accompanied by a positive Ki-67 rate at 5% or more could be considered as an additional marker for further clinical follow-up. Both markers, co-expressed and separate, can give additional information in follow-up patients after treatment for UC.

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

Aims

The Paris System (TPS) was introduced in the diagnostic routine with the goal to simplify and standardise diagnostic reporting of urinary cytology. The diagnostic categories of TPS are based on defined cytological criteria, with a focus on high-grade urothelial carcinoma (HGUC). While the categories ‘negative for HGUC (NHGUC)’ and ‘HGUC’ are straightforward, the categories ‘atypical urothelial cells (AUC)’ and ‘suspicious of HGUC (SHGUC)’ remain inconclusive. In this study, we evaluated the feasibility of TPS in daily practice with special emphasis on ancillary fluorescence in situ hybridisation (FISH) testing in the setting of TPS categories.

Methods

In a 19-month period, TPS was prospectively applied in the routine diagnostic setting on 3900 urinary cytology cases comprising bladder and upper urinary tract washings and voided urine specimens. Additionally, we analysed the results of the FISH assay UroVysion prospectively performed on a cohort of 128 cases enriched for AUC and SHGUC categories.

Results

The most frequently reported category was NHGUC (n=3496, 89.7%), followed by AUC (n=178, 4.6%), HGUC (n=155, 4%), SHGUC (n=61, 1.6%), low-grade urothelial neoplasia (n=6, 0.1%) and other malignancies (n=4, 0.1%). In the FISH cohort, 40/90 (44%) cases within the AUC category were FISH positive, consistent with urothelial neoplasia. In the SHGUC category, 16/21 (76%) cases were FISH positive.

Conclusions

When prospectively applying TPS in urinary cytology, inconclusive atypia accounts only for a small subset of cases. FISH additionally improves the stratification between reactive and malignant cells in the indeterminate AUC and SHGUC categories.

The Paris System for Reporting Urinary Cytology: early review of the literature reveals successes and rare shortcomings

The Paris System for Reporting Urinary Cytology (TPS) provides recommendations for the diagnosis of urinary tract cytology (UTC) specimens and has found acceptance on an international level. Since the official release of TPS in 2016, numerous research studies have been published analyzing its impact. This review summarizes the studies published since the release of TPS, highlighting areas in which TPS has performed well and other areas in which TPS may need improvement.

High-grade urothelial carcinoma in urine cytology with jet black and smooth or glassy chromatin

BACKGROUND

Some high-grade urothelial carcinomas (UCs) in urine cytology can have jet black, smooth, or glassy chromatin, but to the authors' knowledge, the incidence and criteria for diagnosis are not well described. The current study was performed to define the incidence and appearance of high-grade UC in urine cytology in cytospin preparations with jet black and smooth or glassy chromatin.

METHODS

Cytospin preparations from 331 cases with biopsy follow-up (230 benign/low-grade UCs and 101 malignant UCs) were reviewed.

RESULTS

Cases with malignant cells with jet black and smooth or glassy chromatin were identified in a total of 60 cases (59.4% of all malignancies). These comprised 18 carcinoma in situ cases, 28 high-grade papillary UCs, 8 invasive UCs, 3 squamous cell carcinomas, 2 adenocarcinomas, and 1 melanoma. Of the 93 high-grade UCs, 51 (54.8%) had cells with either jet black and smooth or glassy chromatin. These cells were the only type of malignant cell in 6 of 101 cases (5.9%). All cases had at least 50 cells with jet black nuclei. Nuclei with jet black and smooth chromatin often were smaller than normal urothelial cells, often but not always elongate, had irregular nuclear outlines including pointed areas, and usually were accompanied by necrosis. Cells with glassy chromatin often were larger than normal urothelial cells, had rounder but still irregular nuclei, and also had frequent necrosis.

CONCLUSIONS

Malignant urothelial cells in urine cytology with jet black chromatin are common and can be diagnosed as "positive for malignancy" based on their irregular nuclear outline, increased cellularity (≥50 abnormal cells), and frequent necrosis. Cancer Cytopathol 2018;126:64-8. © 2017 American Cancer Society.

p16/Ki-67 dual labeling and urinary cytology results according to the New Paris System for Reporting Urinary Cytology: Impact of extended follow-up

BACKGROUND

Overexpression of p16^INK4a has been identified in urothelial malignancies both cytologically and histologically. In addition, p16/Ki-67 dual labeling has been shown to identify high-grade urothelial cancer cells and some progression cases within a 12-month delay. The Paris System for Reporting Urinary Cytology (TPS) was published in late 2015. Its aim is to clarify the criteria for diagnosing or, conversely, excluding high-grade urothelial carcinoma (HGUC).

METHODS

Dual labeling was performed on archived ThinPrep-based Papanicolaou slides. A total of 208 samples (negative for high-grade urothelial carcinoma [NHGUC], 59; consistent with low-grade urothelial neoplasia [LGUN], 24; atypical urothelial cells [AUC], 15; and suspicious for or showing HGUC, 110) were analyzed for p16/Ki-67 after reclassification according to TPS. We assessed the oncologic status of the patients with cystoscopy, urinary cytology, histology, and prolonged 36-month follow-up data.

RESULTS

The sensitivity of p16/Ki-67 for life-threatening lesions was not different from that of urinary cytology (82.8% vs 83.6%; P = 1). However, among patients with samples classified as NHGUC and AUC, disease-free survival was significantly shorter for dual-labeled cases versus cases with negative dual labeling (P < .0001). The same tendency was observed in patients with histologically proven LGUN (P < .0001). As for specificity in patients with negative cystoscopy and cytology combined, prolonged follow-up showed 90% overall survival at 24 months.

CONCLUSIONS

A long-term evaluation of p16/Ki-67 dual labeling may identify HGUC and progression in cases with negative/low-grade urinary cytology results, and there are potential implications for the clinical management of patients after the conservative treatment of non-muscle-invasive urothelial carcinoma. Cancer Cytopathol 2017;125:552-62. © 2017 American Cancer Society.