Urothelial Carcinoma with Divergent Histologic Differentiation (Mixed Histologic Features) Predicts the Presence of Locally Advanced Bladder Cancer When Detected at Transurethral Resection

Advances, recognition, and interpretation of molecular heterogeneity among conventional and subtype histology of urothelial carcinoma (UC): a survey among urologic pathologists and comprehensive review of the literature

AIMS

Urothelial carcinoma (UC) demonstrates significant molecular and histologic heterogeneity. The WHO 2022 classification has hinted at adding molecular signatures to the morphologic diagnosis. As morphology and associated molecular repertoire may potentially translate to choices of and response to therapy and relapse rate, broader acceptability of recognizing these key features among uropathologists is needed. This prompted an international survey to ascertain the practice patterns in classical/subtype UC among uropathologists across the globe.

METHODS AND RESULTS

A survey instrument was shared among 98 uropathologists using SurveyMonkey software. Anonymized respondent data were analysed. The response rate was 85%. A majority were in concordance with the profiles of luminal (93%) and basal (82%) types. Opinion on the FGFR3 testing platform was variable. While 95% concurred that TERT promoter mutation is the key driver in UC, 72% had the opinion that APOBEC mutagenesis is the main signature in muscle invasive bladder cancer (MIBC). Uropathologists have divergent opinions on MIBC and ERCC2 mutations. Among the participants, 94% would quantify aggressive micropapillary and sarcomatoid histology, while 88% would reevaluate another transurethral resection of the bladder tumour specimen in nonmuscle invasive tumour with micropapillary, small cell, or sarcomatoid histology. A leading number agreed to specific molecular signatures of micropapillary (93%), plasmacytoid (97%), and small cell (86%) subtypes. Ninety-six percent of participants agreed that a small-cell component portends a more aggressive course and should be treated with neoadjuvant chemotherapy and 63% would perform HER2/neu testing only on oncologist's request in advanced tumours. Ninety percent agreed that microsatellite instability testing, although not a standard protocol, should be considered in young patients with upper tract UC. Eighty-six percent agreed that UC with high tumour mutational burden would be a better candidate for immunotherapy.

CONCLUSION

In the era of precision medicine, enhanced understanding of molecular heterogeneity of UC will contribute to better therapeutic options, novel biomarker discovery, innovative management protocols, and outcomes. Our survey provides a broad perspective of pathologists' perceptions and experience regarding incorporation of histomolecular approaches to "personalize" therapy. Due to variable clinical adoption, there is a need for additional data using uniform study criteria. This will drive generation of best practice guidelines in this area for widespread and consistent clinical utility.

The Impact of Fibroblast Growth Factor Receptor Alterations in Clinical Outcomes of Patients With Advanced Urothelial Carcinoma: Real-World Data From a Latin American Population

INTRODUCTION

Fibroblast growth factor receptor (FGFR) mutations and fusions are relevant biomarkers in metastatic urothelial carcinoma (mUC). However, the prevalence of genomic alterations and their impact on clinical outcomes in a Latin American population remains unknown. This study aimed to explore the prevalence of FGFR mutations and/or fusions in patients with mUC in Latin America (LATAM) and its association with clinicopathological characteristics, Bellmunt's prognostic model, and survival outcomes.

PATIENTS AND METHODS

A multicenter retrospective cohort study from 2016 to 2019 of patients with mUC from several LACOG LATAM institutions. FGFR alterations were analyzed by real-time PCR and/or next-generation sequencing in tumor samples and clinicopathologic characteristics and survival outcomes data were collected. The prevalence of FGFR, patient characteristics, and treatment in real-world settings were summarized. Kaplan-Meier survival estimates and Cox regression analyses were used to evaluate the associations of FGFR mutation and/or fusion status with median overall survival (mOS), median time to treatment failure (mTTF), and clinicopathological characteristics.

RESULTS

In total, 222 patients were screened. Of these, 196 patients were considered eligible and were included in the analysis. FGFR mutations and/or fusions were found in 35 (17.9%) patients. There was no statistical difference in mOS and mTTF in FGFR-altered and non-altered patients (13.1 vs. 16.8 months, P = .20 and 3.9 vs. 4.1 months, P = .96, respectively). Bellmunt's prognostic model correctly predicted overall survival (P = .049).

CONCLUSIONS

This is the largest study evaluating the prevalence of FGFR alterations in patients with mUC in the LATAM population. FGFR alterations in mUC were found in 17.9% of the patients, and the presence of this biomarker was not associated with OS. We validated Bellmunt's prognostic model in this cohort.

Hybrid Bladder Tumor: Urothelial Carcinoma With Squamous Cell Differentiation, Urothelial Sarcomatoid Carcinoma, and Concurrent Primary Mucinous Adenocarcinoma With Metastasis to the Penis

The most common histological variants of bladder cancer include urothelial, squamous, and adenocarcinoma. In high-grade, invasive urothelial carcinoma, divergent differentiation can be observed, including glandular, squamous, trophoblastic, and small-cell types. Urothelial sarcomatoid carcinoma is characteristic of advanced carcinomas and is considered a possible common end route for all epithelial carcinomas. Adenocarcinoma of the bladder refers exclusively to true glandular carcinomas. Hybrid tumors are extremely rare and consist of more than one tumor type within the total tumor mass. Penile metastases are extremely uncommon, and there are no reported cases of metastatic adenocarcinoma of the bladder in the literature.

The association between variant histology and prognostic, histomorphological and clinical aspects of bladder urothelial carcinoma

This study underscores the imperative consideration of histological subtypes and divergent differentiation in accurately estimating bladder urothelial carcinoma prognosis and guiding treatment decisions. A comparative analysis was conducted, examining clinical, histological, and prognostic factors between conventional urothelial carcinoma and urothelial carcinoma with variant histology in a clinical sample. A retrospective analysis of slides and other clinicopathologic data was conducted these cases, with an emphasis on key diagnostic elements. We examined 829 cases of urothelial carcinoma of the bladder, comprising of 744 transurethral resection (TUR) and 85 radical cystectomy (RS) specimens, an analysis that showed that 80.5 % (667 cases) were conventional urothelial carcinoma (CUC) and that 19.5 % (162 cases) exhibited variant histology (hereafter "urothelial carcinoma with subtype histology" [UCSH]). TNM classifications for the RS cases were as follows: 2 cases were stage group 0a, 11 stage group 1, 16 stage group 2, 45 stage group 3a, 2 stage group 3b, 1 stage group 4a, and 8 stage group 4b. Only 2 of the RS cases were found to be non-invasive. Among 744 TUR specimens, 387 were found to have a non-invasive tumor whereas 357 had invasive tumors. The most prevalent subtype in the UCSH group was urothelial carcinoma with squamous differentiation, accounting for 54.3 % (88 cases). Notably, 8.02 % (13 cases) exhibited more than one histological subtype. Papillary configuration, histological grade, lamina propria, muscularis mucosa and serosa invasion, lymphovascular invasion, presence of urothelial carcinoma in situ, and overall survival significantly differed between the UCSH and CUC groups (p < 0.05). However, mean age, gender, tumor size, lymphocytic response, disease-free survival, and survival status did not differ significantly (p > 0.05). Among the UCSH group, lower levels of papillary configuration, higher histological grade, higher degree of lamina propria, muscularis mucosa and serosa invasion, and the presence of carcinoma in situ corresponded to higher percentage of histological subtype morphology (p < 0.05). No significant difference in survival status was observed between the groups with and without subtype histology (p = 0.083). This study found that clinical and histopathological prognostic factors associated with a more aggressive disease were linked to the presence and percentage of histological subtypes. Recognizing histological subtype is crucial for treatment decisions and prognosis prediction in urothelial carcinoma cases with these subtypes.

The Prognostic Significance of Histological Subtypes in Patients with Muscle-Invasive Bladder Cancer: An Overview of the Current Literature

Bladder cancer (BC) is the tenth most commonly diagnosed malignancy worldwide. In approximately 25% of cases, it presents as a muscle-invasive disease, requiring a radical treatment. Traditionally, the mainstay of treatment has been radical cystectomy (RC), but in the last decade, bladder-sparing treatments have been gaining growing interest. In particular, trimodal therapy (TMT) seems to yield survival results comparable to RC with less morbidity and better quality of life (QoL) outcomes. In this scenario, we aimed at shedding light on the role of the histological subtypes (HS) of BC and their prognostic significance in muscle-invasive BC (MIBC), treated either surgically or with TMT. We performed a narrative review to provide an overview of the current literature on this topic. When compared with patients diagnosed with conventional urothelial carcinoma (UC) of the same disease stage, survival did not appear to be significantly worse across the reports. But when sub-analyzed for separate subtype, some appeared to be independently associated with adverse survival outcomes such as the micropapillary, plasmacytoid, small-cell, and sarcomatoid subtypes, whereas others did not. Moreover, the optimal management remains to be defined, also depending on the therapeutic susceptibility of each histology. From this perspective, multi-disciplinary assessment alongside the routine inclusion of such entities in randomized clinical trials appears to be essential.

Pathology focused review of morphologic subtypes and molecular variants of urothelial carcinoma with an emphasis on clinical/treatment relevance

Urothelial carcinoma (UC) has significant morbidity, mortality, and remains the most financially costly carcinoma to manage and treat. This review will cover special morphologic features of UC that may be noted by the pathologist and any subsequent significance in terms of clinical management or treatment considerations as mentioned or recommended in the latest WHO 2022 classification of GU tumors. Many important potentially therapy altering morphologic findings can be consistently identified and reported on routine microscopic examination of hematoxylin and eosin (H&E) stained slides. Furthermore, there has been a rapid advancement of molecular diagnostics and tailored therapies throughout oncology, and we will briefly highlight some of these as they relate to the management of UC. We will actively attempt to limit the discussion of histologic descriptions or pathologic diagnostic criteria of these entities and focus rather on the recognition of their importance/implication for clinicians who must make clinical management decisions based upon these findings. Finally, the importance of open lines of communication with the pathologists who review clinical specimens as well as their practice and reporting methods cannot be overstated.

Clinicopathological risk factors associated with tumor relapse of upper tract urothelial carcinoma after radical nephroureterectomy: A single institution 20-year experience

Upper tract urothelial carcinoma (UTUC) is a relatively rare yet aggressive malignancy. While radical nephroureterectomy (RNU) remains the cornerstone treatment, UTUC has high local and metastatic relapse rates, leading to a dismal prognosis. To identify the clinicopathological factors associated with an increased risk of local and metastatic relapse in UTUC, we conducted a retrospective analysis of 133 consecutive UTUC patients who underwent RNU from 1998 to 2018. Patients lost to follow-up or with a history of bladder cancer were excluded from the study. The remaining 87 patients were categorized into two subgroups: those with tumor recurrence/relapse (40 cases) and those without recurrence/relapse (47 cases). Clinical and pathological characteristics were compared across the two groups. Multiple factors are associated with UTUC recurrence/relapse including larger tumor size, histology divergent differentiations/subtypes, high tumor grade, advanced pathologic T stage, positive margin, lymphovascular invasion (LVI), positive lymph node status, and preoperative hydronephrosis. Multivariate Cox regression analysis revealed that squamous differentiation predicted recurrence/relapse (p = 0.012), independent of tumor stage. Moreover, compared to the conventional histology type, UTUC with squamous differentiation had a significantly higher relapse rate (p = 0.0001) and poorer survival (p = 0.0039). This observation was further validated in invasive high-grade UTUC cases. Our findings suggest that many pathological factors contribute to UTUC recurrence/relapse, particularly, squamous differentiation may serve as an independent risk predictor for relapse and a potent prognosticator for adverse cancer-specific survival in UTUC patients. Recognizing and thoroughly assessing the pathological factors is essential for better oncologic management of UTUC.

Molecular Pathology of Urothelial Carcinoma

Urothelial carcinoma is characterized by the presence of a wide spectrum of histopathologic features and molecular alterations that contribute to its morphologic and genomic heterogeneity. It typically harbors high rates of somatic mutations with considerable genomic and transcriptional complexity and heterogeneity that is reflective of its varied histomorphologic and clinical features. This review provides an update on the recent advances in the molecular characterization and novel molecular taxonomy of urothelial carcinoma and variant histologies.

[Rare tumors and tumor types of the urinary system in the 5th edition of the WHO classification 2022]

The 5th edition of the World Health Organization (WHO) classification of tumors of the urinary tract and male genital organs introduced both general and specific changes in structure, classification, and nomenclature. This also applies to rarer tumors and tumor subtypes of the urinary system. Knowledge of these changes is relevant for routine histopathological work. This article provides an overview of the main new features of the rarer tumors and tumor subtypes of the urinary system in the new edition of the WHO classification.

Glandular Lesions of the Urinary Bladder: Diagnostic and Molecular Updates

Glandular lesions in the urinary tract or their associated pathologies can pose a diagnostic challenge. There is a variety of benign alterations and tumor types that need to be taken into account in differential diagnostic considerations. In recent times, efforts for better defining these alterations or lesions both on the histopathological and molecular levels have been undertaken. This article will provide an update on current diagnostic and molecular considerations of these lesions.

Impact of variant histology on upstaging and survival in patients with nonmuscle invasive bladder cancer undergoing radical cystectomy

INTRODUCTION

Variant histology (VH) of urothelial carcinoma is uncommon and frequently presents at the muscle-invasive stage. VH is considering a significant risk factor for progression among patients with nonmuscle invasive bladder cancer (NMIBC). While there is some debate, expert opinion is generally that upfront radical cystectomy (RC) should be consider for these patients. Limited data exists to support this position. In this study, we sought to examine the rate of upstaging and overall survival for patients with VH NMIBC against patients with pure urothelial NMIBC who underwent RC, to help clarify the optimal treatment strategy for these patients.

METHODS

The institutional REDCap database was utilized to identify all patients with T1 and Ta bladder cancer that underwent RC over the study period (2004-2022). Matched-pair analysis was performed between patients with VH and pure urothelial NMIBC; 42 pairs were matched on prior intravesical therapy, presence of muscularis propria on transurethral resection of bladder tumor (TURBT), any carcinoma in situ presence on prior TURBTs, and final tumor staging on TURBT. The primary outcomes of interest were pathologic tumor upstaging rate at RC and overall survival. Secondary outcomes of interest included association of demographic or pretreatment variables with upstaging, and upstaging rates for specific variant histologies.

RESULTS

Patients with VH NMIBC undergoing RC were upstaged at a significantly higher rate than a matched cohort of patients with pure urothelial NMIBC (73.8% vs. 52.4%, P = 0.0244) and among those upstaged, had significantly higher rates of pT3 to pT4 (54.7% vs. 23.8%, P = 0.0088). Rate of node positivity at RC for VH NMIBC was also higher compared to pure urothelial NMIBC (40.5% vs. 21.4%, P = 0.0389). Among histologic variants, patients with plasmacytoid and sarcomatoid subtypes demonstrated the highest rates of upstaging; differences were not statistically significant. The overall median survival was 28.4 months for patients with VH after RC compared to 155.1 months for patients with pure urothelial NMIBC (P = 0.009).

CONCLUSION

Patients with VH NMIBC undergoing RC are at significantly higher risk of upstaging at RC when compared to patients with pure urothelial NMIBC and have worse overall survival. While this study supports the concept of an aggressive treatment approach for patients with VH NMIBC, improvements in understanding of the disease are necessary to improve outcomes.

Oncologic outcomes of intravesical therapy in the management of nonmuscle invasive bladder cancer with variant histology

PURPOSE

There is limited data on oncologic outcomes in nonmuscle invasive bladder cancer (NMIBC) with variant histology (VH) managed with intravesical therapy. We sought to evaluate oncologic outcomes for this cohort at a high-volume center.

MATERIALS AND METHODS

A retrospective review of an IRB-approved bladder cancer database was performed. Patients with a history of NMIBC with VH present on transurethral resection of bladder tumor (TURBT) treated with intravesical therapy (BCG or chemotherapy) were identified. Outcomes of interest included recurrence within the bladder, progression to muscle-invasive bladder cancer (MIBC), metastatic progression, cancer-specific, and overall survival. Survival time was computed from the date of initiation of intravesical therapy to the date of event or censoring. For patients who underwent radical cystectomy, recurrence-free, cancer-specific, and overall survival were also computed. The Kaplan-Meier method with log rank was utilized to compare survival time between VH sub-groups.

RESULTS

Ninety patients were included in the final cohort with a median follow-up of 38 months. The majority of patients had T1 disease (72%) and received intravesical BCG (83%) as their only form of intravesical therapy. The most commonly represented VH in this series were glandular and squamous differentiation (26%). Forty-eight patients (53%) experienced recurrence within the bladder with a median recurrence-free survival of 24 months (95% Confidence Interval [CI]: 2-46 months). Five-year rates of progression to MIBC and distant metastasis were both 14% respectively. Twenty-six patients (28%) eventually required cystectomy. When stratifying by VH, patients with sarcomatoid, plasmacytoid, and micropapillary had significantly worse oncologic outcomes.

CONCLUSION

In this series of highly-selected patients with NMIBC and VH, bladder-sparing treatment with intravesical therapy demonstrated acceptable oncologic outcomes for most VHs. This may be an acceptable treatment option for patients without plasmacytoid, sarcomatoid, or micropapillary features who are not suitable cystectomy candidates or who prioritize bladder-sparing treatment.

Urinary tract cytology showing variant morphology and divergent differentiation

Urothelial carcinoma represents a diverse group of tumours with distinct histologic subtypes, each exhibiting unique cytomorphologic features, architectural growth patterns, and/or well-developed aberrant differentiation. In fact, there are more than 13 subtypes of urothelial carcinoma recognized in the 2022 WHO classification of tumours in the urinary tract. The identification of these subtypes is crucial for an accurate diagnosis of urothelial carcinoma, and many have important clinical implications. Variant/divergent features may coexist with conventional high-grade urothelial carcinoma (HGUC) or present with 100% variant morphology. In urinary tract cytology (UTC), urothelial carcinoma can display divergent differentiation, such as squamous, glandular, or small cell carcinoma differentiation. The use of cell block preparations and immunohistochemistry with available residual urine can enhance diagnostic accuracy. On the other hand, identifying urothelial carcinoma variants, including nested, micropapillary, and plasmacytoid subtypes, poses significant challenges in UTC. Many cases of these variants are only detected retrospectively after variant histology has been established from resection specimens. Moreover, some variants exhibit features inconsistent with the diagnostic criteria for HGUC according to the Paris System for Reporting Urinary Tract Cytology. Nevertheless, the rarity of pure variant morphology and the occurrence of some false negatives for these variant cases are essential to maintain the specificity of UTC overall. This review covers the histology, cytomorphology, and important clinical aspects observed in urothelial carcinoma exhibiting divergent differentiation and various urothelial carcinoma variants detected in UTC.

[Morphological variants of the invasive urothelial cell carcinoma.]

Urothelial cell carcinoma is the most common malignant tumor of the urinary tract, which develops in the renal pelvis, ureter, and bladder, and rarely it develops in the ureter. Histologically, urothelial cell carcinoma is categorized into non-invasive and invasive forms. Non-invasive urothelial cell carcinoma has papillary growth, it is usually well differentiated, and has a favorable outcome, while invasive urothelial cell carcinoma infiltratively spreads the organs of origin, it is typically poorly differentiated, and often associated with a poor prognosis. In the case of invasive urothelial cell carcinoma, the clinical course is primarily determined by the depth of invasion, but according to recent data, morphological variants of urothelial cell carcinoma respond differently to oncological treatments, and their biological behavior is also distinct. These subtypes and variants are significantly underdiagnosed in Hungary and internationally because the criteria for histological diagnosis are not clear for many subsets. The latest 2022 WHO classification of urinary tract tumors significantly clarified the definitions of various subtypes and variants. In this paper, utilizing the current classification, we review and explain these subtypes' morphological, immunohistochemical, differential diagnostic, prognostic, and predictive characteristics intending to make them appear as much as possible in everyday diagnostic practice. Also, the work aims to present the individual urothelial cell carcinoma subtypes and variants to the Hungarian community of pathologists, oncologists, and urologists, so that the previously high level of urological oncology care can become even more personalized. Orv Hetil. 2023; 164(40): 1567-1582.

The Impact of Variant Histology in Patients with Urothelial Carcinoma Treated with Radical Cystectomy: Can We Predict the Presence of Variant Histology?

Considering the divergent biological behaviors of certain histological subtypes of urothelial carcinoma, it would be of great importance to examine the impact of variant histology and to predict its presence in patients with bladder cancer. A single-center cohort study included 459 patients who underwent radical cystectomy for urothelial carcinoma between 2017 and 2021. Patients were followed up with until July 2022. We compared clinical, laboratory, and histopathologic characteristics and the overall survival between patients with pure urothelial carcinoma and variant histologies. Our results showed that the patients with variant histology were older and preoperatively more frequently had hydronephrosis and higher values of leukocytes and neutrophils. Also, we found a significant association between variant histology and an advanced stage of tumor disease, the presence of lymphovascular invasion, positive surgical margins, and metastases in surgically resected lymph nodes. The number of neutrophils was identified as an independent preoperative predictor of the presence of variant histology after a radical cystectomy. The overall survival of the patients with variant histology was significantly lower compared to the patients with pure urothelial carcinoma. According to our results, the presence of variant histology represents a more aggressive form of the disease. Preoperative neutrophil counts may indicate the presence of variant histology of urothelial carcinoma in patients with bladder cancer.

Morphology, immunohistochemistry characteristics, and clinical presentation of microcystic urothelial carcinoma: a series of 10 cases

BACKGROUND

Microcystic urothelial carcinoma (MUC) is a rare variant of urothelial carcinoma with histological appearances similar to begin lesions. Thus far, approximately 50 cases have been reported. Here, we investigated the clinicopathological features of MUC.

METHODS

Clinical data and paraffin-embedded tissue blocks were collected. Immunohistochemical staining and polymerase chain reaction-Sanger sequencing were performed to detect the phenotype and TERT mutation status of MUC, respectively.

RESULTS

The mean patient age was 58.8 ± 14.5 years, with a male predominance (8:2). The pathological stage was T1 in one case, T2 in three cases, T3 in four cases, and T4 in two cases. Tumor metastases or death occurred in all five patients who were followed up within 1-3 years. Histological analyses revealed microcystic, tubular, cribriform, and occasionally cord-like structures, which generally lacked interstitial reactions. The lumens were empty, contained eosinophilic secretion, or were filled with mucin. The microcysts/tubules/cribriform patterns were lined by flat, cuboid, signet ring, or columnar types of epithelia. The cuboid, signet ring, and columnar types represented "glandular metaplasia" or glandular differentiation of urothelial carcinoma. Immunohistochemistry analyses revealed distinct co-expression patterns involving the luminal markers FOXA1 and GATA3, as well as the basal markers CK5/6 and CD44. All 10 cases exhibited a luminal phenotype according to the GATA3+/CK14- criterion, whereas nine cases exhibited a luminal phenotype according to the FOXA1+/CK14- criterion. The telomerase reverse transcriptase-C228T mutation was detected in seven cases.

CONCLUSIONS

MUC is a rare variant with a deceptively benign form of urothelial carcinoma, which is generally identified as a late-stage tumor with a poor prognosis. It exhibits distinct co-expression of luminal and basal markers, along with the TERT-C228T mutation.

Utility of GATA-3 and associated immunohistochemical markers in the differential diagnosis of poorly differentiated urothelial carcinoma

Aims

The aims are to study the utility of GATA-3 along with panel of immunohistochemical (IHC) markers in the differential diagnosis of primary and metastatic poorly differentiated urothelial carcinoma (UC).

Settings and Design

This is a prospective and retrospective observational study.

Subjects and Methods

Poorly differentiated carcinomas of urinary tract and metastatic sites from January 2016 to December 2017 were subjected to a panel of four IHC markers including GATA-3, p63, Cytokeratin (CK) 7, and CK20. Additional markers such as p16, an enzyme called alpha-methylacyl-CoA racemase, CDX2, and thyroid transcription factor 1 were also done depending on the morphology and site.

Statistical Analysis Used

The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of GATA-3 in making the diagnosis of UC were calculated.

Results

Forty-five cases were included in the study and after appropriate IHC, the diagnosis was resolved as UC in 24 cases. GATA-3 was positive in 83.33% of UC; all the four markers positive in 33.33% and all negative in 4.17% of UC. However, at least one of the four markers was present in 95.83% of UC, except in sarcomatoid UC. GATA-3 had 100% specificity in differentiating from prostate adenocarcinoma.

Conclusion

GATA-3 is a useful marker in the diagnosis of UC in the primary and metastatic sites with a sensitivity of 83.33%. GATA-3 along with other IHC markers in correlation with clinical and imageological features is necessary for making specific diagnosis of poorly differentiated carcinoma.

Clinicopathologic analysis of patients undergoing repeat transurethral resection of bladder tumour following an initial diagnosis of urothelial carcinoma with lamina propria invasion and variant/divergent histology

AIMS

A subset of patients with urothelial carcinoma (UCa) and lamina propria (LP) invasion in bladder biopsies/transurethral resections (TURs) are at significant risk for recurrence and have increased rates of progression to UCa with muscularis propria (MP) invasion. The clinicopathologic features of this patient population has not been well characterised in the Pathology literature.

METHODS

We performed a search through our urologic pathology files and expert consult cases of the senior author for bladder biopsies/TURs of UCa with LP invasion and variant/divergent histology from 2014 to 2020. Patients with a prior diagnosis of UCa with MP invasion or upper tract UCa were excluded. Clinicopathologic data were obtained.

RESULTS

Ninety-five patients with at least one biopsy/TUR of UCa with LP invasion and variant/divergent histology were identified. Mean patient age was 72 years (range: 46-92 years) with a male predominance 2.3:1. Initial variant/divergent histologies identified were: glandular (35.8%), squamous (23.2%), micropapillary (20%), clear cell/lipid rich (12.6%), diffuse/signet ring/plasmacytoid (10.5%), nested (9.5%), sarcomatoid (6.3%), poorly differentiated/anaplastic (4.2%), small cell (2.1%), lymphoepithelioma-like (2.1%), osteoclast-like giant cells (1.1%) and tumour giant cells (1.1%). Two or more variant histologies were identified in 18.9% of these cases. The rate of micropapillary UCa was significantly higher in multifocal tumours compared with unifocal tumours (37% vs 7.1%).

CONCLUSIONS

In our cohort of patients undergoing early repeat biopsy/TUR, 75% of patients had persistent UCa. Additionally, almost 25% of patients had a prior diagnosis of UCa without a variant/divergent histology identified. Our findings highlight the critical role of repeat biopsy/TUR especially in a subset of patients who have variant/divergent histology, even in the absence of MP invasion.

Recent Advances in the Classification of Bladder Cancer - Updates from the 5th Edition of the World Health Organization Classification of the Urinary and Male Genital Tumors

BACKGROUND

The World Health Organization Classification (WHO) of Urinary and Male Genital Tumors has recently been updated to its 5th edition. The new edition presents a comprehensive approach to the classification of urinary and male genital tumors with an incorporation of morphologic, clinical, and genomic data.

OBJECTIVE

This review aims to update the new classification of bladder cancer in the 5th edition and to highlight important changes in nomenclatures, diagnostic criteria, and molecular characterization, as compared to the 4th edition.

METHODS

The pathologic classification of bladder cancer in the 5th edition of WHO Classification of Urinary and Male Genital Tumours was compared to that in the 4th edition. PubMed was searched using key words, including bladder cancer, WHO 1973, WHO 1998, WHO 2004, WHO 2016, histology, pathology, genomics, and molecular classification in the time frame from 1973 to August of 2022. Other relevant papers were also consulted, resulting in the selection of 81 papers as references.

RESULTS

The binary grading of papillary urothelial carcinoma (UC) is practical, but it may be oversimplified and contribute to "grade migration" in recent years. An arbitrary cutoff (5%) has been proposed for bladder cancers with mixed grades. The diagnosis of papillary urothelial neoplasm with low malignant potential has been dramatically reduced in recent years because of overlapping morphology and treatment with low-grade papillary UC. An inverted growth pattern should be distinguished from true (or destructive) stromal invasion in papillary UC. Several methods have been proposed for pT1 tumor substaging, but it is often challenging to substage pT1 tumors in small biopsy specimens. Bladder UC shows a high tendency for divergent differentiation, leading to several distinct histologic subtypes associated with an aggressive clinical behavior. Molecular classification based on the genomic analysis may be a useful tool in the stratification of patients for optimal treatment.

CONCLUSIONS

The 5th edition of WHO Classification of Urinary and Male Genital Tumours has made several significant changes in the classification of bladder cancer. It is important to be aware of these changes and to incorporate them into routine clinical practice.

Characterisation of tumour-immune phenotypes and PD-L1 positivity in squamous bladder cancer

AIMS

Immune checkpoint inhibitor (ICI) therapy has become a viable treatment strategy in bladder cancer. However, treatment responses vary, and improved biomarkers are needed. Crucially, the characteristics of immune cells remain understudied especially in squamous differentiated bladder cancer (sq-BLCA). Here, we quantitatively analysed the tumour-immune phenotypes of sq-BLCA and correlated them with PD-L1 expression and FGFR3 mutation status.

METHODS

Tissue microarrays (TMA) of n = 68 non-schistosomiasis associated pure squamous cell carcinoma (SCC) and n = 46 mixed urothelial carcinoma with squamous differentiation (MIX) were subjected to immunohistochemistry for CD3, CD4, CD8, CD56, CD68, CD79A, CD163, Ki67, perforin and chloroacetate esterase staining. Quantitative image evaluation was performed via digital image analysis.

RESULTS

Immune infiltration was generally higher in stroma than in tumour regions. B-cells (CD79A) were almost exclusively found in stromal areas (sTILs), T-lymphocytes and macrophages were also present in tumour cell areas (iTILs), while natural killer cells (CD56) were nearly missing in any area. Tumour-immune phenotype distribution differed depending on the immune cell subset, however, hot tumour-immune phenotypes (high density of immune cells in tumour areas) were frequently found for CD8 + T-cells (33%), especially perforin + lymphocytes (52.2%), and CD68 + macrophages (37.6%). Perforin + CD8 lymphocytes predicted improved overall survival in sq-BLCA while high PD-L1 expression (CPS ≥ 10) was significantly associated with higher CD3 + , CD8 + and CD163 + immune cell density and high Ki67 (density) of tumour cells. Furthermore, PD-L1 expression was positively associated with CD3 + /CD4 + , CD3 + /CD8 + and CD68 + /CD163 + hot tumour-immune phenotypes. FGFR3 mutation status was inversely associated with CD8 + , perforin + and CD79A + lymphocyte density.

CONCLUSIONS

Computer-based image analysis is an efficient tool to analyse immune topographies in squamous bladder cancer. Hot tumour-immune phenotypes with strong PD-L1 expression might pose a promising subgroup for clinically successful ICI therapy in squamous bladder cancer and warrant further investigation.

Diagnostic Value of the Vesical Imaging-Reporting and Data System in Bladder Urothelial Carcinoma with Variant Histology

The value of the Vesicle Imaging-Reporting and Data System (VI-RADS) in the diagnosis of muscle-invasive bladder cancer (MIBC) for urothelial carcinoma with variant histology (VUC) remains unknown. We retrospectively evaluated 360 consecutive patients with bladder cancer (255 pure urothelial carcinoma [PUC] and 69 VUC) who underwent multiparametric magnetic resonance imaging between 2011 and 2019. VI-RADS scores assigned by four readers were significantly higher for the VUC group than for the PUC group (p < 0.05). In the cohort of 122 pair-matched patients, there was no significant difference in VI-RADS score distribution between the PUC and VUC groups for all readers (p > 0.05). The area under the receiver operating characteristic curve for MIBC diagnosis via overall VI-RADS score was 0.93-0.94 for PUC and 0.89-0.92 for VUC, with no significant difference between the PUC and VUC groups (p = 0.32-0.60). These data suggests that VI-RADS scores achieved high diagnostic performance for detection of muscle invasion in both PUC and VUC. PATIENT SUMMARY: The Vesical Imaging-Reporting and Data System (VI-RADS) is a standardized system for reporting on detection of muscle-invasive bladder cancer via magnetic resonance imaging (MRI) scans. Our study shows that VI-RADS is also highly accurate for diagnosis for different variants of muscle-invasive bladder cancer, with good inter-reader agreement.

Bladder Preservation for Muscle-Invasive Bladder Cancer With Variant Histology

A growing body of evidence has shown bladder-preservation with chemo-radiotherapy achieves comparable survival to Radical Cystectomy (5-year OS 50%-70%) and superior quality of life outcomes for patients with muscle-invasive urothelial carcinoma of the bladder (UC). However, up to 55% of patients harbor variant histology and in this review we aim to clarify the role of bladder-preservation for this group. We first draw the distinction between urothelial carcinoma with divergent differentiation (UCDD) and non-urothelial carcinoma (NUC). UCDD is common, increasing in prevalence, and whilst each subtype may have its own characteristics current evidence suggests comparable outcomes with radical cystectomy and bladder-preservation. Non-urothelial carcinoma is a collection of distinct pathologies each deserving of its own management strategy. However, these tumors are rare, and evidence is generated from retrospective studies with significant inherent bias. Small cell carcinoma of the bladder has good evidence for bladder-preservation; however, other pathologies such as Squamous Cell Carcinoma and Adenocarcinoma are not well supported. We recommend careful multidisciplinary appraisal of the evidence for each subtype and honest patient discussion about the limited evidence before reaching management decisions. As we look to the future molecular-profiling may help better characterize these tumors and aid in treatment selection.

Urothelial Carcinoma: Divergent Differentiation and Morphologic Subtypes

Urothelial carcinoma (UC) is known to encompass a wide spectrum of morphologic features and molecular alterations. Approximately 15% to 25% of invasive UC exhibits histomorphologic features in the form of "divergent differentiation" along other epithelial lineages, or different "subtypes" of urothelial or sarcomatoid differentiation. It is recommended that the percentage of divergent differentiation and or subtype(s) be reported whenever possible. Recent advances in molecular biology have led to a better understanding of the molecular underpinning of these morphologic variations. In this review, we highlight histologic characteristics of the divergent differentiation and subtypes recognized by the latest version of WHO classification, with updates on their molecular and clinical features.

Urothelial Carcinoma: Update on Staging and Reporting, and Pathologic Changes Following Neoadjuvant Chemotherapies

Staging and reporting of cancers of the urinary tract have undergone major changes in the past decade to meet the needs for improved patient management. Substantial progress has been made. There, however, remain issues that require further clarity, including the substaging of pT1 tumors, grading and reporting of tumors with grade heterogeneity, and following NAC. Multi-institutional collaborative studies with prospective data will further inform the accurate diagnosis, staging, and reporting of these tumors, and in conjunction with genomic data will ultimately contribute to precision and personalized patient management.

The 2022 ENCR Recommendations on recording and reporting of urothelial tumours of the urinary tract

An updated European Network of Cancer registries (ENCR) Recommendations on Recording and Reporting of Urothelial Tumours of the Urinary Tract had been published in 2022. After the publication by the ENCR of the "Recommendations for coding bladder cancers" in 1995, knowledge about the biology and pathology of urinary tract tumors and their classification has varied and increased substantially. On the other hand, several studies have shown that cancer registries use different definitions, criteria for inclusion and coding of urothelial tumors. This great variability among registries affects not only the criteria for recording (registration, coding and classification) but also the criteria of reporting (counting in the statistics of incidence and survival) urinary tract tumors. This causes difficulties in the data comparability from different registries. Recording and reporting of urothelial tumors requires the application of standard criteria that must take into account the combination of the multiple aspects as the primary topography, the histological type, the grade, the extent of invasion, the multi-centricity, the progressions and the time interval between tumors. This led to the creation of a Working Group of the ENCR that developed these recommendations on the recording and reporting of urothelial tumors of the urinary tract. This article reports these recommendations and the rationale for each.

The 2022 World Health Organization Classification of Tumors of the Urinary System and Male Genital Organs-Part B: Prostate and Urinary Tract Tumors

The 2022 World Health Organization (WHO) classification of the urinary and male genital tumors was recently published by the International Agency for Research on Cancer. This fifth edition of the WHO "Blue Book" offers a comprehensive update on the terminology, epidemiology, pathogenesis, histopathology, diagnostic molecular pathology, and prognostic and predictive progress in genitourinary tumors. In this review, the editors of the fifth series volume on urologic and male genital neoplasms present a summary of the salient changes introduced to the classification of tumors of the prostate and the urinary tract.

Clinicopathological Review of Micropapillary Urothelial Carcinoma

PURPOSE OF REVIEW

This review will discuss micropapillary urothelial carcinoma with respect to biology, histopathologic characteristics, genetic and molecular features, diagnosis, clinical management, and future directions of research.

RECENT FINDINGS

Recent consensus opinion study showed only moderate interobserver reproducibility in the diagnostic criteria. The most reproducible criteria with the highest consensus were multiple nests in the same lacunar spaces. There are recent reports of high rates of intratumoral heterogeneity of ERBB2 amplification within tumor containing both micropapillary and classic urothelial components. Micropapillary urothelial carcinoma is a well-documented highly aggressive variant of urothelial carcinoma with proven worse outcomes. Accurate recognition and reporting of this pattern is critical for optimal management. Newer therapeutic strategies related to the molecular and genetic findings seen in MPUC remain to be explored further.

The Accuracy of Transurethral Bladder Resection in Detecting Bladder Cancer Histological Variants and Their Prognostic Value at Radical Cystectomy

Objectives: to investigate the accuracy of transurethral resection of bladder tumours (TURBT) in detecting histological variants (BHV) at radical cystectomy (RC) and to evaluate the impact of TURBT before cystectomy on oncological outcomes. Methods: Data of 410 consecutive RCs were assessed. Positive and negative predictive values were used to assess the accuracy of TURBT in detecting BHV. Cohen’s Kappa coefficient was used to calculate the agreement grade. Logistic regression analysis predicted features based on the presence of BHV at TURBT. Multivariable backward conditional Cox regression analysis was used to estimate oncological outcomes. Results: A total of 73 patients (17.8%) showed BHV at TURBT as compared to 108 (26.3%) at RC. A moderate agreement in histological diagnosis was found between TURBT and RC (0.58). However, sensitivity and specificity in detecting BHV were 56% and 96%, respectively. Furthermore, positive predictive value (PPV) was 84.7% and negative predictive value (NPV) was 84.6%. Presence of BHV at TURBT was an independent predictor for pathologic upstage, albeit not a predictor for positive nodes or positive surgical margins. However, at multivariable analysis adjusted for all confounders, presence of BHV at TURBT was an independent predictor for recurrence after RC, but not for survival. Conversely, the presence of BHV at RC was an independent predictor for both recurrence and survival. Conclusion: There was a moderate agreement between TURBT and RC histopathological findings. TURBT, alone, could not provide an accurate and definitive histological diagnosis. Detection of BHV in TURBT specimens is not an independent predictor of oncological outcomes; indeed, only pathological features at RC are associated with worse survival. However, BHV presence in cystectomy specimens resulted as an independent predictor of both cancer-specific and overall mortality.

Bladder Cancer Sample Handling and Reporting: Pathologist's Point of View

The aim of this narrative review is to provide adequate information on handling and reporting of the bladder cancer samples to improve the closely collaboration between pathologists and urologists. The main (but not exclusive) research tool used was PubMed and 87 references were selected and quoted in the text. We have considered handling of biopsies, transurethral resection (TUR), and cystectomy specimens to summarize the different methods of sampling and the related issues. Moreover, we considered and discussed the main prognostic factors, such as histological tumor type, grade, and stage of bladder cancer, that should be described in the pathological report. In addition, critical issues encountered in the interpretation of histological samples were discussed.

Morphological predictors for microsatellite instability in urothelial carcinoma

Introduction

Microsatellite instability occurs due to a series of mutations in the DNA pairing error repair (Mismatch repair; MMR) genes, which can affect germ cells as occurs in Lynch syndrome, whose patients are at high risk of developing multiple cancers. The loss of MMR protein is commonly determined by immunohistochemical studies. Although the relation between microsatellite instability and urothelial carcinomas has been widely studied, its evaluation is not currently performed in the analysis of urothelial carcinomas.

Methods

In this study, the microsatellite status of 139 urothelial carcinomas was analyzed and their clinicopathological characteristics were evaluated. We identified that 10.3% (13 patients) of urothelial carcinomas had loss of MMR protein expression (9 MLH1; 5 MSH2; 2 PMS2; 2 PSH6; n = 139).

Results

Results suggest that these tumors occur more frequently in males, are more frequently located in the bladder or ureters, and present a high tumor grade with a papillary histological pattern that does not infiltrate the lamina propria or, in the case of infiltrating tumors, that grows into perivesical tissues.

Conclusions

We identified patients with the aforementioned tumor characteristics as patients with a high probability of presenting loss of MMR protein expression, and consider that only these patients should undergo further immunohistochemical and molecular techniques for proper diagnosis. Therefore, we propose that the clinicopathological characteristics found in the present study could become possible markers to determine which cases should undergo additional tests.

Prostatic Ductal Adenocarcinoma Controlled for Tumor Grade, Stage, and Margin Status Does Not Independently Influence the Likelihood of Biochemical Recurrence in Localized Prostate Cancer After Radical Prostatectomy

CONTEXT.—

Prostatic ductal adenocarcinoma (PDA) has historically been considered to be an aggressive subtype of prostate cancer.

OBJECTIVE.—

To investigate if PDA is independently associated with worse biochemical recurrence (BCR)-free survival after radical prostatectomy.

DESIGN.—

A review of 1584 radical prostatectomies was performed to grade, stage, and assess margin status in each tumor nodule. Radical prostatectomies with localized PDA (ie, those lacking metastasis) in the tumor nodule with the highest grade and stage and worst margin status were matched with prostatic acinar adenocarcinoma according to grade, stage, and margin status. The effect of PDA on BCR was assessed by multivariable Cox regression and Kaplan-Meier analyses.

RESULTS.—

Prostatic ductal adenocarcinoma was present in 171 cases. We excluded 24 cases because of lymph node metastasis (n = 13), PDA not in the highest-grade tumor nodule (n = 9), and positive surgical margin in a lower-grade tumor nodule (n = 2). The remaining 147 cases included 26 Grade Group (GG) 2, 44 GG3, 6 GG4, and 71 GG5 cancers. Seventy-six cases had extraprostatic extension, 33 had seminal vesicle invasion, and 65 had positive margins. Follow-up was available for 113 PDA and 109 prostatic acinar adenocarcinoma cases. Prostate-specific antigen density (odds ratio, 3.7; P = .001), cancer grade (odds ratio, 3.3-4.3; P = .02), positive surgical margin (odds ratio, 1.7; P = .02), and tumor volume (odds ratio, 1.3; P = .02) were associated with BCR in multivariable analysis. Prostatic ductal adenocarcinoma, its percentage, intraductal carcinoma, and cribriform Gleason pattern 4 were not significant independent predictors of BCR.

CONCLUSIONS.—

Advanced locoregional stage, higher tumor grade, and positive surgical margin status rather than the mere presence of PDA are more predictive of worse BCR-free survival outcomes following radical prostatectomy in men with a component of PDA.

Bladder cancer histological variants: which parameters could predict the concordance between transurethral resection of bladder tumor and radical cystectomy specimens?

Introduction

The concordance rate of bladder cancer (BCa) histological variants (HV) between transurethral resection of bladder tumor (TURBT) and radical cystectomy (RC) is sub-optimal and is unclear which factors may influence it. The aim of this study was to identify factors that may be correlated to a higher TURBT-RC concordance rate.

Material and methods

Consecutive patients who had undergone RC between 2000 and 2019 at a single Institution with pathological evidence of HV were included. Patients with diagnosis of HV both at RC and at the previous TURBT were enlisted in the TURBT-RC Concordance Group (CG), whereas patients with only evidence of HV at RC in the TURBT-RC Non-Concordance Group (NCG). Surgical factors evaluated were the source of energy (mono- vs bipolar), surgeon’s experience (</≥100), execution of re-TURBT, number and size of specimens at TURBT.

Results

A total of 81 patients were included, 49 (60.5%) in the CG and 32 (39.5%) in the NCG. Among the surgical factors, maximal core length (MCL) was significantly higher in the CG (12.5 vs 10 mm, p = 0.014) (Table 1). At uni- and multivariable analyses, MCL>10 mm represented an independent predictor of concordance [OR 2.95; CI (1.01–8.61); p = 0.048]. Tumor recurrence, focality and dimension, source of energy, surgeon’s experience, performance of re-TURBT and total number of specimens at TURBT did not significantly predict the concordance.

Conclusions

Longer specimens at TURBT yield a higher chance to detect HV before RC. In this light, improving the quality of bladder resection means improving the management of BCa.

Gene Expression Profiling of Muscle-Invasive Bladder Cancer With Secondary Variant Histology

OBJECTIVES

To determine the potential impact of the presence of secondary variant histology on the gene expression profiles of muscle-invasive bladder cancer (MIBC) tumors.

METHODS

For six tumors, revised samples were collected from urothelial and secondary variant components (cohort A). The commercial cohort (cohort B) consisted of the anonymized gene expression profiles of 173 patients with MIBC. Samples were obtained from the clinical use of the Decipher Bladder test that were available as part of the Decipher GRID prospective registry (NCT02609269). Secondary variant presence in cohort B was abstracted from institutional pathology reports. For the commercial cohort, only the urothelial carcinoma component was profiled.

RESULTS

Molecular subtyping of both urothelial and variant components found micropapillary and nested cases were classified as a luminal subtype. Conversely, the sarcomatoid and small cell cases were classified as basal/squamous or neuroendocrine-like, respectively. For cohort B, 50 (29%) of 173 cases had reported secondary variant histology. Cases with squamous variant had basal profiles, small cell cases expressed neuronal markers, and micropapillary cases were classified as luminal. Sarcomatoid tumors had robust epithelial-mesenchymal transition marker expression.

CONCLUSIONS

Our data suggest that in MIBC with secondary variant, the urothelial component can demonstrate an expression profile that closely resembles the variant component.

Association Between Surgical Volume and Survival Among Patients With Variant Histologies of Bladder Cancer

OBJECTIVE

To examine the relationship between hospital volume and the management of bladder cancer variant histology. Variant histologies of bladder cancer are rare which limits the ability for providers to develop expertise however there is a clear hospital and/or surgeon-volume relationship for management of rare or complex surgical and/or medical diseases.

METHODS

We queried the National Cancer Database from 2004-2016 for all cases of bladder cancer, identifying cases of variant histology. Our primary outcome was overall survival while secondary outcomes included identifying treatment patterns. Hospitals were stratified into those that managed ≤2, >2-4, >4-6, and ≥6 cases per year of variant histology.

RESULTS

We identified 23,284 patients with bladder cancer of variant histology who were treated at 1301 hospitals. Few institutions had high volume experience with this disease: 18.5% (n = 241) treated >2 patients annually and 5.7% (n = 76) treated >4 cases annually. Hospital volume positively correlated with utilization of early radical cystectomy (RC) in non-muscle invasive disease and neoadjuvant chemotherapy in muscle-invasive disease. On multivariable analysis, increased hospital volume was associated with improved survival. After stratifying by sub-type, hospital volume continued to be associated with improved survival for squamous, small cell, and sarcomatoid cancers.

CONCLUSION

Management of variant histology urothelial carcinoma at high-volume centers is associated with improved overall survival. The mechanisms of this are multifactorial, and future research should focus on improvement opportunities for low-volume hospitals, centralization of care, and/or increased access to care at high-volume centers.

Updated pathology reporting standards for bladder cancer: biopsies, transurethral resections and radical cystectomies

Aim

Optimal management of bladder cancer requires an accurate, standardised and timely pathological diagnosis, and close communication between surgeons and pathologists. Here, we provide an update on pathology reporting standards of transurethral resections of the bladder and cystectomies.

Methods

We reviewed recent literature, focusing on developments between 2013 and 2021.

Results

Published reporting standards developed by pathology organizations have improved diagnosis and treatment. Tumor sub-staging and subtyping has gained increased attention. Lymph nodes continue to be an area of debate, and their staging has seen minor modifications. Several tasks, particularly regarding specimen preparation (“grossing”), are not yet standardized and offer opportunity for improvement. Molecular classification is rapidly evolving, but currently has only limited impact on management.

Conclusion

Pathological reporting of bladder cancer is continuously evolving and remains challenging in some areas. This review provides an overview of recent major developments, with a particular focus on published reporting standards.

Expression of Nectin-4 in Bladder Urothelial Carcinoma, in Morphologic Variants, and Nonurothelial Histotypes

The antibody-drug conjugate enfortumab-vedotin acts by targeting nectin-4, a protein that is nearly ubiquitously expressed in conventional urothelial cancer. However, expression of nectin-4 in morphologic variants of urothelial carcinoma and nonurothelial histotypes was unknown. Immunohistochemistry for nectin-4 using was performed on 169 patients including 83 with nonmuscle invasive bladder cancer and 86 patients with muscle invasive bladder cancer. Staining was scored for intensity (0 to 3) and extent (% positive cells) using the histological score system, where >15 was considered positive. Overall, 72/83 (87%) samples of nonmuscle invasive urothelial carcinoma were positive, including 29/30 (97%) noninvasive papillary urothelial carcinomas, 7/8 (87.5%) carcinomas in situ, 36/45 (80%) papillary urothelial carcinomas invading the lamina propria. Overall, 50/86 muscle invasive tumors were positive, including 15/22 (68.2%) urothelial carcinomas, 7/10 (70%) squamous cell carcinomas, 3/11 (28%) micropapillary tumors, 4/6 (66%) adenocarcinomas, 2/4 (50%) nested carcinomas, 5/8 (63%) plasmacytoid, 1/10 (10%) sarcomatoid carcinomas, and 0/15 (0%) small cell carcinomas. Whole transcriptome RNA sequencing revealed that compared with conventional urothelial carcinomas, most sarcomatoid carcinomas and all but 2 small cell carcinomas expressed very low levels of nectin-4 mRNA but expressed significant levels of either trop2 or ERBB2, which are the molecular targets of 2 other antibody-drug conjugates-sacituzumab gavitecan (trop2) or trastuzumab deruxtecan (ERBB2/HER2). In summary, our study demonstrates that there is heterogeneity of expression of nectin-4 in morphologic variants of urothelial cancer and nonurothelial histotypes, and suggests that testing expression of nectin-4 should be considered in morphologic variants or nonurothelial histotypes found to have lower expression.

Molecular Pathology of Urothelial Carcinoma

Urothelial carcinoma is characterized by the presence of a wide spectrum of histopathologic features and molecular alterations that contribute to its morphologic and genomic heterogeneity. It typically harbors high rates of somatic mutations with considerable genomic and transcriptional complexity and heterogeneity that is reflective of its varied histomorphologic and clinical features. This review provides an update on the recent advances in the molecular characterization and novel molecular taxonomy of urothelial carcinoma and variant histologies.

Accuracy of Transurethral Resection of the Bladder in Detecting Variant Histology of Bladder Cancer Compared with Radical Cystectomy

BACKGROUND

Correct identification of variant histologies (VHs) of bladder cancer (BCa) at transurethral resection of the bladder (TURB) could drive the subsequent treatment.

OBJECTIVE

To evaluate the concordance in detecting VHs between TURB and radical cystectomy (RC) specimens in BCa patients.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analyzed 1881 BCa patients who underwent TURB and subsequent RC at seven tertiary care centers between 1980 and 2018. VHs were classified as sarcomatoid, lymphoepithelioma-like, neuroendocrine, squamous, micropapillary, glandular, adenocarcinoma, nested, and other variants.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Concordance between TURB and RC was defined as the ability to achieve histological subtypes at TURB confirmed at RC specimen, and was expressed according to Cohen's kappa coefficient.

RESULTS AND LIMITATIONS

Of the patients, 14.6% and 21% were diagnosed with VH at TURB and RC specimens, respectively. The most common VHs at TURB were squamous, neuroendocrine, and micropapillary carcinoma (5.2%, 1.5%, and 1.5%, respectively). At RC, the most frequent VHs were squamous, micropapillary, and sarcomatoid carcinoma (7.2%, 3.0%, and 2.7%, respectively). The overall concordance in detecting VH was defined as slight concordance (coefficient: 0.18). Moderate concordance was found for neuroendocrine, adenocarcinoma, and squamous carcinoma (coefficient: 0.49, 0.47, and 0.41, respectively). Micropapillary, glandular, and other variants showed slight concordance (coefficient: 0.05, 0.17, and 0.12, respectively), while nested and sarcomatoid carcinoma showed fair concordance (coefficient: 0.32 and 0.26, respectively). Results may be limited by the absence of centralized pathological analysis.

CONCLUSIONS

A non-negligible percentage of patients were diagnosed with VH at both TURB and RC. TURB showed relatively low accuracy, ranging from poor to moderate, in detecting VHs. Our study underlines the need of additional diagnostic tools in order to identify VHs properly at precystectomy time and to improve patient survival outcomes.

PATIENT SUMMARY

In this report, we underlined the low accuracy of transurethral resection of the bladder in detecting variant histologies and the need for additional diagnostic tools.

Imaging and Management of Bladder Cancer

Simple Summary

Bladder cancer is a complex disease, the sixth most common cancer, and one of the most expensive cancers to treat. In the last few decades, there has been a significant decrease in the bladder cancer-related mortality rate, potentially related to decreased smoking prevalence, improvements in diagnosing bladder cancer, and advances in treatment. Those advances in diagnostic tools and therapies and greater understanding of the disease are helping to evolve how bladder cancer is managed. The purpose of this article is to provide a review of bladder cancer pathology, diagnosis, staging, radiologic imaging, and management, and highlight recent developments and research.

Abstract

Methods: Keyword searches of Medline, PubMed, and the Cochrane Library for manuscripts published in English, and searches of references cited in selected articles to identify additional relevant papers. Abstracts sponsored by various societies including the American Urological Association (AUA), European Association of Urology (EAU), and European Society for Medical Oncology (ESMO) were also searched. Background: Bladder cancer is the sixth most common cancer in the United States, and one of the most expensive in terms of cancer care. The overwhelming majority are urothelial carcinomas, more often non-muscle invasive rather than muscle-invasive. Bladder cancer is usually diagnosed after work up for hematuria. While the workup for gross hematuria remains CT urography and cystoscopy, the workup for microscopic hematuria was recently updated in 2020 by the American Urologic Association with a more risk-based approach. Bladder cancer is confirmed and staged by transurethral resection of bladder tumor. One of the main goals in staging is determining the presence or absence of muscle invasion by tumor which has wide implications in regards to management and prognosis. CT urography is the main imaging technique in the workup of bladder cancer. There is growing interest in advanced imaging techniques such as multiparametric MRI for local staging, as well as standardized imaging and reporting system with the recently created Vesicle Imaging Reporting and Data System (VI-RADS). Therapies for bladder cancer are rapidly evolving with immune checkpoint inhibitors, particularly programmed death ligand 1 (PD-L1) and programmed cell death protein 1 (PD-1) inhibitors, as well as another class of immunotherapy called an antibody-drug conjugate which consists of a cytotoxic drug conjugated to monoclonal antibodies against a specific target. Conclusion: Bladder cancer is a complex disease, and its management is evolving. Advances in therapy, understanding of the disease, and advanced imaging have ushered in a period of rapid change in the care of bladder cancer patients.

High-grade Urothelial Carcinoma with Malignant Melanocytic Differentiation

Urothelial carcinoma usually shows divergent differentiation and variant histology with squamous and glandular morphology being most common. In this report, we present a case of divergent malignant melanocytic differentiation in a high-grade urothelial carcinoma. A 98-year-old East Asian woman with an anterior bladder wall mass underwent resection, which revealed a high-grade poorly differentiated tumor. A minor component of high-grade papillary urothelial carcinoma and carcinoma in situ is also present. The majority of the tumor cells are morphologically and immunohistochemically consistent with melanoma, a minority of cells are positive for urothelial markers, and rare cells coexpress both melanocytic and urothelial markers. Cells that express melanocytic markers or urothelial markers are intimately admixed together. Taken together, a diagnosis of high-grade urothelial carcinoma with malignant melanocytic differentiation was rendered. This is the first report in the literature of malignant melanocytic differentiation in a high-grade urothelial carcinoma, a finding that may have important diagnostic and therapeutic implications.

Non-Muscle Invasive Bladder Cancer with Variant Histology: Biological Features and Clinical Implications

BACKGROUND

The most common bladder cancer (BC) histotype is pure urothelial carcinoma (UC), which may undergo divergent differentiation in some cases. Variant histology (VH) presents along variable morphologies, either single or combined between them or with pure UC. From a clinical standpoint, the vast majority of BC is diagnosed at non-invasive or minimally invasive stages, namely as non-muscle invasive BC (NMIBC). There is a wide range of therapeutic options for patients with NMIBC, according to their clinical and pathological features. However, current risk stratification models do not show optimal effectiveness. Evidence from the literature suggests that VH has peculiar biological features, and may be associated with poorer survival outcomes compared to pure UC.

SUMMARY

In order to describe the biological features and prognostic/predictive role of VH in NMIBC, and to discuss current treatment options, we performed a systematic literature search through multiple databases (PubMed/Medline, Google Scholar) for relevant articles according to the following terms, single and/or in combination: "non-muscle invasive bladder cancer," "variant histology," "micropapillary variant," "glandular differentiation," "squamous differentiation," "nested variant," "plasmacytoid variant," and "sarcomatoid variant." We extracted 99 studies including original articles, reviews, and systematic reviews, and subsequently analyzed data from 16 studies reporting on the outcome of NMIBC with VH. We found that the relative rarity of these forms as well as the heterogeneity in study populations and therapeutic protocols results in conflicting findings overall. Key Messages: The presence of VH should be taken into account when counseling a patient with NMIBC, since it may upgrade the disease to high-risk tumor and thus warrant a more aggressive treatment.

Clinical outcomes after intravesical bacillus Calmette-Guérin for the highest-risk non-muscle-invasive bladder cancer newly defined in the Japanese Urological Association Guidelines 2019

OBJECTIVE

To assess the clinical outcomes of highest-risk non-muscle-invasive bladder cancer patients treated with intravesical bacillus Calmette-Guérin.

METHODS

The medical charts of patients with non-muscle-invasive bladder cancer treated with intravesical bacillus Calmette-Guérin between 2000 and 2018 at a single institution were retrospectively reviewed. Patients were stratified into three groups (intermediate-, high- and highest-risk groups) according to the risk classification of the updated Japanese Urological Association guidelines 2019. Among the three groups, the intravesical recurrence-free survival and progression-free survival were estimated and compared, respectively. Furthermore, the different types of risk factors in the highest-risk group were analyzed.

RESULTS

Of the 165 patients, 49 (30%) patients had intravesical recurrence and 23 (14%) patients showed progression to muscle-invasive disease during a median follow-up period of 53 months. Significant differences were not noted in the recurrence-free survival and progression-free survival among the three groups. Multivariable survival analysis of 74 patients in the highest-risk group showed that carcinoma in situ in the prostatic urethra was a significant predictor associated with recurrence (hazard ratio 3.20, P = 0.026) and progression (hazard ratio 4.36, P = 0.013).

CONCLUSIONS

Intravesical bacillus Calmette-Guérin can control highest-risk non-muscle-invasive bladder cancer in most patients. Our findings might aid in decision-making regarding the treatment of this subset of patients who require intensive treatment, such as intravesical therapy with bacillus Calmette-Guérin and radical cystectomy.

Squamous differentiation is a potential biomarker predicting tumor progression in patients treated with pembrolizumab for urothelial carcinoma

Immune checkpoint inhibitor (ICI) is widely used and highly effective for some cancer patients but may result in disease progression in others. Hyperprogressive disease in particular is characterized by an acceleration of tumor growth during ICI therapy and has been reported in patients including those with urothelial carcinoma. Biomarkers predicting treatment efficacy are crucial to avoid tumor progression and unnecessary adverse effects. This study aims to clarify the predictors of disease progression for ICI treatment in patients with urothelial carcinoma. We analyzed the response pattern of 23 urothelial carcinomas treated with pembrolizumab and its association with pathological features and potential immunohistochemical markers including EGFR, MDM2, p53, p16, and programmed cell death ligand-1 (PD-L1) expression and CD8- and CD204-positive cell infiltration. During ICI therapy, 13 (57 %) patients showed progressive disease including 6 (26 %) with hyperprogressive disease. Notably, squamous differentiation combined with MAC387 expression was observed exclusively in cases with progressive disease (6 of 13, 46 %); it was not present in cases with stable disease or partial/complete response (0 of 10, p = 0.0019). All tumors with squamous differentiation showed positive staining for EGFR. Additionally, the loss of p16 expression occurred more frequently in cases with progressive disease (8 of 13, 62 %) than in other cases (3 of 10, 30 %), but this finding did not reach statistical significance. Squamous differentiation was also significantly associated with shorter overall survival. Based on our observations, squamous differentiation may be a novel biomarker for predicting disease progression in patients with urothelial carcinoma who receive pembrolizumab.

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

BACKGROUND: Despite recent advances in the management of muscle-invasive bladder cancer (MIBC), treatment outcomes remain suboptimal, and variability exists across current practice patterns. OBJECTIVE: To promote standardization of care for MIBC in Canada by developing a consensus guidelines using a multidisciplinary, evidence-based, patient-centered approach who specialize in bladder cancer. METHODS: A comprehensive literature search of PubMed, Medline, and Embase was performed; and most recent guidelines from national and international organizations were reviewed. Recommendations were made based on best available evidence, and strength of recommendations were graded based on quality of the evidence. RESULTS: Overall, 17 recommendations were made covering a broad range of topics including pathology review, staging investigations, systemic therapy, local definitive therapy and surveillance. Of these, 10 (59% ) were level 1 or 2, 7 (41% ) were level 3 or 4 recommendations. There were 2 recommendations which did not reach full consensus, and were based on majority opinion. This guideline also provides guidance for the management of cisplatin-ineligible patients, variant histologies, and bladder-sparing trimodality therapy. Potential biomarkers, ongoing clinical trials, and future directions are highlighted. CONCLUSIONS: This guideline embodies the collaborative expertise from all disciplines involved, and provides guidance to further optimize and standardize the management of MIBC.

Smoke load prognostic impact on bacillus Calmette-Guérin (BCG) treated non-muscle invasive bladder cancer

PURPOSE

Smoking habit is the major risk factor for bladder cancer (BC), related to about 50% of these tumors; however, the tobacco dose-effect impact on BC immune treatment is underexplored. This study evaluates the impact of smoke load on non-muscle invasive bladder cancer (NMIBC) prognosis after intravesical BCG.

METHODS

Smoke load, recurrence, progression and disease-specific survival were evaluated in a retrospective study including NMIBC patients treated with intravesical BCG between 2006 and 2015. Multivariate Cox regression, ROC and Kaplan-Meier curves were utilized.

RESULTS

132 pT1 NMIBC patients were included: 95 (72%) males, mean age 69.6 ± 10.5 years and mean smoking pack-years 22.0 ± 20.8. Recurrence, progression and disease-specific death occurred in 69 (52.3%, mean 20.55 ± 20.44 months), 22 (16.7%, mean 31.39 ± 20.19 months) and 11 (8.3%, mean 37.23 ± 18.34 months), respectively. Smoke load significantly impacted recurrence, HR = 1.019 (95% CI 1.008-1.030, p = 0.0004), and progression, HR = 1.034 (95% CI 1.016-1.052, p = 0.0002), but not survival. For every 1-year increment in pack-years, the risk of relapse and progression increases by 1.9% and 3.4%, respectively. Over 20 pack-year showed the best predictive prognostic power.

CONCLUSION

The smoke load has a potential prognostic role in terms of recurrence and progression in the BCG treated NMIBC. Future studies should explore the smoking impact on the immune system, mainly beyond 20 pack-year.