Contemporary bladder cancer: Variant histology may be a significant driver of disease

Pitfalls of frozen section diagnosis in ureter margin evaluation of plasmacytoid urothelial carcinoma of urinary bladder

BACKGROUND

Plasmacytoid urothelial carcinoma (PUC) is a rare and aggressive subtype that often presents at advanced stages with poor prognosis. This study investigated tumor invasion to better understand tumor behavior and potentially to improve management strategies by comparing the clinicopathologic characteristics of PUC with positive ureter resection margin (+ URM) with PUC with negative URMs (-URM).

METHODS

This retrospective analysis used pathology reports from 2017 to 2023 for cases diagnosed with PUC during radical cystectomy (RC). All applicable H&E slides of RC specimens were reviewed. Cases with a plasmacytoid component greater than 25% in the RC specimens were analyzed. Frozen section analyses (FSAs) and permanent section analyses (PSAs) of ureter resection margins were performed.

RESULTS

Fifteen patients with a plasmacytoid component greater than 25% in their RC specimens were identified. Compared with -URM PUC cases, +URM PUC cases were located more frequently at the trigone or bladder neck, and all + URM cases exhibited ureter orifice involvement. Among 6 PSA-positive cases, three (50%) cases showed discrepancies with FSA. Three + URM cases exhibited PUC tumor cells along the submucosa and muscularis propria layer, and the 3 remaining cases showed PUC tumor cells along the adventitia. We observed a consistent adventitia invasion in all the discordant cases, with sectioning errors and misinterpretation identified as the primary causal factors.

CONCLUSION

To the best of our knowledge, this is the first study to demonstrate two separate patterns of tumor infiltration along the ureter and to discuss the significance of comparing FSA with PSA in PUC. The significance of comprehensive management strategies for PUC patients, including a thorough evaluation of ureteral margins and accurate interpretation of periureteral fat tissue, is highlighted. Large, well-designed studies are needed to strengthen the evidence and to establish optimal management strategies for patients with PUC.

Prognostic impact of histological discordance between transurethral resection and radical cystectomy

OBJECTIVE

To analyse the impact of histological discordance of subtypes (subtypes or divergent differentiation [DD]) in specimens from transurethral resection (TUR) and radical cystectomy (RC) on the outcome of the patients with bladder cancer receiving RC.

PATIENTS AND METHODS

We analysed data for 2570 patients from a Japanese nationwide cohort with bladder cancer treated with RC between January 2013 and December 2019 at 36 institutions. The non-urinary tract recurrence-free survival (NUTR-FS) and overall survival (OS) stratified by TUR or RC specimen histology were determined. We also elucidated the predictive factors for OS in patients with subtype/DD bladder cancer.

RESULTS

At median follow-up of 36.9 months, 835 (32.4%) patients had NUTR, and 691 (26.9%) died. No statistically significant disparities in OS or NUTR-FS were observed when TUR specimens were classified as pure-urothelial carcinoma (UC), subtypes, DD, or non-UC. Among 2449 patients diagnosed with pure-UC or subtype/DD in their TUR specimens, there was discordance between the pathological diagnosis in TUR and RC specimens. Histological subtypes in RC specimens had a significant prognostic impact. When we focused on 345 patients with subtype/DD in TUR specimens, a multivariate Cox regression analysis identified pre-RC neutrophil-lymphocyte ratio and pathological stage as independent prognostic factors for OS (P = 0.016 and P = 0.001, respectively). The presence of sarcomatoid subtype in TUR specimens and lymphovascular invasion in RC specimens had a marginal effect (P = 0.069 and P = 0.056, respectively).

CONCLUSION

This study demonstrated that the presence of subtype/DD in RC specimens but not in TUR specimens indicated a poor prognosis. In patients with subtype/DD in TUR specimens, pre-RC neutrophil-lymphocyte ratio and pathological stage were independent prognostic factors for OS.

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.

Molecular profile of bladder cancer progression to clinically aggressive subtypes

Bladder cancer is a histologically and clinically heterogenous disease. Most bladder cancers are urothelial carcinomas, which frequently develop distinct histological subtypes. Several urothelial carcinoma histological subtypes, such as micropapillary, plasmacytoid, small-cell carcinoma and sarcomatoid, show highly aggressive behaviour and pose unique challenges in diagnosis and treatment. Comprehensive genomic characterizations of the urothelial carcinoma subtypes have revealed that they probably arise from a precursor subset of conventional urothelial carcinomas that belong to different molecular subtypes - micropapillary and plasmacytoid subtypes develop along the luminal pathway, whereas small-cell and sarcomatoid subtypes evolve along the basal pathway. The subtypes exhibit distinct genomic alterations, but in most cases their biological properties seem to be primarily determined by specific gene expression profiles, including epithelial-mesenchymal transition, urothelial-to-neural lineage plasticity, and immune infiltration with distinct upregulation of immune regulatory genes. These breakthrough studies have transformed our view of bladder cancer histological subtype biology, generated new hypotheses for therapy and chemoresistance, and facilitated the discovery of new therapeutic targets.

A meta-analysis of UCA1 accuracy in the detection of bladder cancer

INTRODUCTION

Bladder cancer (BCa) exhibits a relatively high prevalence, yet convenient tools for its early detection are lacking. Our study aims to assess the diagnostic value of Urothelial Carcinoma-Associated 1 (UCA1) in the early detection of BCa.

METHODS

Systematic searches were performed in electronic databases (PubMed, Web of Science, Science Direct, CNKI, Wanfang, and VIP) until 20 July 2023. QUADAS-2 was used for quality assessment, while Meta-DiSc 1.4 and STATA 14.0 were employed for statistical analysis.

RESULTS

A total of 1252 BCa patients and 779 controls, from 12 identified articles, were included. UCA1 showed strong discriminatory ability in BCa detection, with an overall sensitivity of 0.84 specificity of 0.91, and a 0.91 area under the curve (AUC). Strikingly, UCA1 expressed in urine and tissue exhibited higher diagnostic value (0.92 AUC) compared to that in blood (0.86 AUC). Furthermore, urine UCA1 demonstrated remarkable diagnostic performance with 91% sensitivity and 98% specificity. Deeks' funnel plot detected no substantial publication bias.

CONCLUSION

UCA1 could serve as a potential biomarker for BCa detection with good diagnostic performance. Besides, compared to UCA1 in blood, urine and tissue UCA1 exhibited higher diagnostic value. Further prospective clinical research is needed to corroborate the conclusion.

PROSPERO REGISTRATION

CRD42023463210.

Current Advances in the Management of Nonurothelial Subtypes of Bladder Cancer

Urothelial cancer (UC) is the most common histology seen in bladder tumors. The 2022 WHO classification of urinary tract tumors includes a list of less common subtypes (formerly known as variants) for invasive UC which are considered high-grade tumors. This review summarizes the most recent advances in the management of selected nonurothelial subtypes of bladder cancer: squamous cell carcinoma, small cell carcinoma, sarcomatoid urothelial carcinoma, micropapillary carcinoma, plasmacytoid carcinoma, adenocarcinoma, and urachal carcinoma. The role of neoadjuvant and adjuvant chemotherapy has not been well characterized for most of these histologies, and prospective data are extremely limited. Participation in clinical trials is recommended in advanced disease.

Neoadjuvant Chemotherapy Prior to Radical Cystectomy for Muscle-Invasive Bladder Cancer With Variant Histology: A Systematic Review and Meta-Analysis of Survival Outcomes and Pathological Features

PURPOSE

To conduct systematic review and meta-analysis to evaluate effects of neoadjuvant chemotherapy (NAC) on survival and histopathological outcomes of variant histology (VH) of urothelial carcinoma (UC) of bladder.

METHODS

This systematic review was registered in PROSPERO (CRD42023389115). Literature search was conducted in PubMed/Medline, Embase, and Cochrane Library for studies published up to January 2023. Population, intervention, comparator, outcome, and study design were as follows: bladder cancer patients with VH (population), neoadjuvant chemotherapy (intervention), radical cystectomy only (comparators), oncological survival and pathologic response (outcomes), and retrospective or prospective (study design).

RESULTS

Finally, a total of 17 studies were included in the present study (quantitative analysis, n = 17; qualitative analysis, n = 12). Pooled HR was 0.49 (95% CI: 0.31-0.76; P = .002) for OS. Pooled HR was 0.61 (95% CI: 0.38-0.98; P = .04) for CSS. Pooled HR was 0.44 (95% CI: 0.21-0.93; P = .03) in PFS. Pooled OR was 6.61 (95% CI: 4.50-9.73; P < .00001) in complete pathologic response. Pooled OR was 9.59 (95% CI: 3.56-25.85; P < .00001) in any pathologic response. Evidence quality assessments for each 5 comparisons using the GRADE approach were that Certainty was moderate in 1, low in 1, and very low in 3.

CONCLUSIONS

Administration of NAC before surgery in bladder cancer patients with VH might confer better survival outcomes and higher pathologic down staging rate than no administration of NAC before surgery.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 2: Grading of Mixed Grade, Invasive Urothelial Carcinoma Including Histologic Subtypes and Divergent Differentiations, and Non-Urothelial Carcinomas

The 2022 International Society of Urological Pathology (ISUP) Consensus Conference on Urinary Bladder Cancer Working Group 2 was tasked to provide evidence-based proposals on the applications of grading in noninvasive urothelial carcinoma with mixed grades, invasive urothelial carcinoma including subtypes (variants) and divergent differentiations, and in pure non-urothelial carcinomas. Studies suggested that predominantly low-grade noninvasive papillary urothelial carcinoma with focal high-grade component has intermediate outcome between low- and high-grade tumors. However, no consensus was reached on how to define a focal high-grade component. By 2004 WHO grading, the vast majority of lamina propria-invasive (T1) urothelial carcinomas are high-grade, and the rare invasive low-grade tumors show only limited superficial invasion. While by 1973 WHO grading, the vast majority of T1 urothelial carcinomas are G2 and G3 and show significant differences in outcome based on tumor grade. No consensus was reached if T1 tumors should be graded either by the 2004 WHO system or by the 1973 WHO system. Because of the concern for underdiagnosis and underreporting with potential undertreatment, participants unanimously recommended that the presence of urothelial carcinoma subtypes and divergent differentiations should be reported. There was consensus that the extent of these subtypes and divergent differentiations should also be documented in biopsy, transurethral resection, and cystectomy specimens. Any distinct subtype and divergent differentiation should be diagnosed without a threshold cutoff, and each type should be enumerated in tumors with combined morphologies. The participants agreed that all subtypes and divergent differentiations should be considered high-grade according to the 2004 WHO grading system. However, participants strongly acknowledged that subtypes and divergent differentiations should not be considered as a homogenous group in terms of behavior. Thus, future studies should focus on individual subtypes and divergent differentiations rather than lumping these different entities into a single clinicopathological group. Likewise, clinical recommendations should pay attention to the potential heterogeneity of subtypes and divergent differentiations in terms of behavior and response to therapy. There was consensus that invasive pure squamous cell carcinoma and pure adenocarcinoma of the bladder should be graded according to the degree of differentiation. In conclusion, this summary of the International Society of Urological Pathology Working Group 2 proceedings addresses some of the issues on grading beyond its traditional application, including for papillary urothelial carcinomas with mixed grades and with invasive components. Reporting of subtypes and divergent differentiation is also addressed in detail, acknowledging their role in risk stratification. This report could serve as a guide for best practices and may advise future research and proposals on the prognostication of these tumors.

Successful bladder-sparing partial cystectomy for muscle-invasive domal urothelial carcinoma with sarcomatoid differentiation: a case report

High-grade (HG) urothelial carcinoma (UC) with variant histology has historically been managed conservatively. The presented case details a solitary lesion of muscle-invasive bladder cancer (MIBC) with sarcomatoid variant (SV) histology treated by partial cystectomy (PC) and adjuvant chemotherapy. A 71-year-old male with a 15-pack year smoking history presented after outside transurethral resection of bladder tumor (TURBT). Computerized tomography imaging was negative for pelvic lymphadenopathy, a 2 cm broad-based papillary tumor at the bladder dome was identified on office cystoscopy. Complete staging TURBT noted a final pathology of invasive HG UC with areas of spindle cell differentiation consistent with sarcomatous changes and no evidence of lymphovascular invasion. The patient was inclined toward bladder-preserving options. PC with a 2 cm margin and bilateral pelvic lymphadenectomy was performed. Final pathology revealed HG UC with sarcomatoid differentiation and invasion into the deep muscularis propria, consistent with pathologic T2bN0 disease, a negative margin, and no lymphovascular invasion. Subsequently, the patient pursued four doses of adjuvant doxorubicin though his treatment was complicated by hand-foot syndrome. At 21 months postoperatively, the patient developed a small (<1 cm) papillary lesion near but uninvolved with the left ureteral orifice. Blue light cystoscopy and TURBT revealed noninvasive low-grade Ta UC. To date, the patient has no evidence of HG UC recurrence; 8 years after PC. Patient maintains good bladder function and voiding every 3-4 h with a bladder capacity of around 350 ml. Surgical extirpation with PC followed by adjuvant chemotherapy may represent a durable solution for muscle invasive (pT2) UC with SV histology if tumor size and location are amenable. Due to the sparse nature of sarcomatous features within UC, large multicenter studies are required to further understand the clinical significance and optimal management options for this variant histology.

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.

Prognostic value of the sarcomatoid component in bladder cancer: A propensity score matching study

Sarcomatoid carcinoma of the bladder is rare, and little is known about the prognostic impact of the proportion of sarcomatoid components of the bladder. The present study aimed to assess the prognostic value of the proportion of sarcomatoid components with regard to death and recurrence rates in patients with bladder cancer (BC), and to validate the worse survival results of sarcomatoid carcinomas of the bladder using propensity score matching. Patients with sarcomatoid carcinoma of the bladder who were treated at the Affiliated Hospital of Qingdao University between August 2010 and May 2021 were included in the study. A 1:2 propensity score matching system based on age, sex and pathological T stage was used for sarcomatoid and non-sarcomatoid carcinoma matching. Finally, 114 patients with BC were included. Patients with sarcomatoid carcinoma had worse 5-year cancer-specific survival (CSS) (69.1 vs. 86.9%; log-rank P=0.008) and recurrence-free survival (RFS) (64.1 vs. 83.6%; log-rank P=0.001) rates compared with patients with non-sarcomatoid carcinoma, as had the subgroup with muscle invasion. Multivariate analysis revealed sarcomatoid carcinoma as an independent prognostic factor. Patients with a low proportion of sarcomatoid components (1-50%) had a better prognosis than patients with a high proportion (>50%), and no significant difference was found compared with the non-sarcomatoid group. Overall, a proportion of sarcomatoid components >50% was a predictor of CSS and RFS. Sarcomatoid components markedly increased the risk of death and recurrence in muscle-invasive BC, but not in non-muscle-invasive BC. A higher proportion of sarcomatoid components was significantly associated with poorer survival.

Radical cystectomy in non-metastatic sarcomatoid bladder cancer: A direct comparison vs urothelial bladder cancer

INTRODUCTION

The effect of radical cystectomy (RC) on cancer-specific mortality (CSM) is unclear in non-metastatic sarcomatoid bladder cancer (SBC) patients. We aimed to test the benefit of RC in SBC, and to perform a direct comparison vs urothelial bladder cancer (UCB).

MATERIALS AND METHODS

Within the Surveillance, Epidemiology, and End Results database (SEER 2001-2018) all non-metastatic SBC and UBC patients were identified. Endpoint of interest was CSM. Propensity score matching (PSM), cumulative incidence plots, competing risks regression (CRR) analyses, three-months landmark analyses, and sensitivity analyses were performed. All results were stratified according to organ-confined (OC: T₂N₀M₀) vs non-organ-confined (NOC: T_3-4N₀M₀ or T_anyN_1-3M₀) stages.

RESULTS

Of 554 SBC patients, 49 vs 51% harbored OC vs NOC stages. Of 47,741 UBC patients, 62 vs 38% harbored OC vs NOC stages. RC rates were 33 vs 67% in OC vs NOC-SBC patients, and 40 vs 60% in OC vs NOC-UBC patients. After 1:1 PSM, comparison between RC vs no-RC was performed in OC-SBC (67 patients per group), OC-UBC (7611 patients per group), NOC-SBC (63 patients per group), and NOC-UBC patients (4644 patients per group). CRR hazard ratios associated with RC vs no-RC were 0.37 (p < 0.001) in OC-SBC vs 0.45 (p < 0.001) in OC-UBC, and 0.56 (p = 0.01) in NOC-SBC vs 0.68 (p < 0.001) in NOC-UBC. These results were replicated in sensitivity and landmark analyses.

CONCLUSIONS

The protective effect of RC vs no-RC is stronger in SBC than UBC patients, regardless of OC vs NOC stages.

Histological variants and lymphovascular invasion in upper tract urothelial carcinoma can stratify prognosis after radical nephroureterectomy

OBJECTIVES

Patients with histological variants (HV) of bladder cancer have more advanced disease and poorer survival rates than those with pure urothelial carcinoma (UC). Moreover, lymphovascular invasion (LVI) is an important biomarker after RNU in systematic reviews and meta-analyses. Thus, here we investigated the clinical and prognostic impact of HV and LVI in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy (RNU).

METHODS

Data from 223 UTUC patients treated with RNU without neoadjuvant chemotherapy were retrospectively evaluated. We analyzed differences in clinicopathological features and survival rates between patients with pure UC and those with HV. Conditional survival (CS) analysis was performed to obtain prognostic information over time.

RESULTS

A total of 32 patients (14.3%) had HV, with the most common variant being squamous differentiation, followed by glandular differentiation. UTUC with HV was significantly associated with advanced pathological T stage (pT ≥ 3), higher tumor grade (G3), and LVI, compared to pure UC (all P < 0.01). Progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS), were all significantly worse in the HV group compared to the pure UC group (all, P < 0.001). In multivariable analysis, HV and LVI were independent predictors of CSS and OS. We classified the patients into three groups using these two predictors: low-risk (neither HV nor LVI), intermediate-risk (either HV or LVI), and high-risk (both HV and LVI). Significant differences in PFS, CSS, and OS rates were found among the 3 groups. In CS analysis, the conditional PFS, CSS, and OS rates at 1, 2, 3, 4, and 5 years improved with increased duration of event-free survival. CS analysis revealed that most progression events occurred within 2 years after RNU, and patients with risk factors had worse PFS at all time points.

CONCLUSIONS

A risk model using HV and LVI can stratify PFS, CSS, and OS of patients treated with RNU. In addition, CS analysis revealed that HV and LVI were poor prognostic factors over time after RNU.

Filling the gaps in the research about second primary malignancies after bladder cancer: Focus on race and histology

Purpose

Previous research has shown that bladder cancer has one of the highest incidences of developing a second primary malignancy. So, we designed this study to further examine this risk in light of race and histology.

Patients and methods

Using the surveillance, epidemiology, and end results (SEER) 18 registry, we retrospectively screened patients who had been diagnosed with bladder cancer between 2000 and 2018. We then tracked these survivors until a second primary cancer diagnosis, the conclusion of the trial, or their deaths. In addition to doing a competing risk analysis, we derived standardized incidence ratios (SIRs) and incidence rate ratios (IRRs) for SPMs by race and histology.

Results

A total of 162,335 patients with bladder cancer were included, and during follow-ups, a second primary cancer diagnosis was made in 31,746 of these patients. When the data were stratified by race, SIRs and IRRs for SPMs showed a significant difference: Asian/Pacific Islanders (APIs) had a more pronounced increase in SPMs (SIR: 2.15; p 0.05) than White and Black individuals who had an SIRs of 1.69 and 1.94, respectively; p 0.05. In terms of histology, the epithelial type was associated with an increase in SPMs across all three races, but more so in APIs (IRR: 3.51; 95% CI: 2.11-5.85; p 0.001).

Conclusion

We found that race had an impact on both the type and risk of SPMs. Additionally, the likelihood of an SPM increases with the length of time between the two malignancies and the stage of the index malignancy.

Bladder Urothelial Carcinoma: Machine Learning-based Computed Tomography Radiomics for Prediction of Histological Variant

RATIONALE AND OBJECTIVES

Histological variant (HV) of bladder urothelial carcinoma (UC) is a significant factor for therapy management. We aim to assess the predictive performance of machine learning (ML)-based Computed Tomography radiomics of UC for HV.

MATERIALS AND METHODS

Volume of interest of 37 bladder UC tumors, of which 21 were pure and 16 were HV, were manually segmented. The extracted first- and second-order texture features (n = 117) using 3-D Slicer radiomics were compared to the radical cystectomy histopathological results. ML algorithms were performed to determine the significant models using Python 2.3, Pycaret library. The sample size was increased to 74 by synthetic data generation, and three outliers from the training set were removed (training dataset; n = 52, test dataset; n = 19). The predictive performances of 15 ML algorithms were compared. Then, the best two models were evaluated on the test set and ensembled by Voting Classifier.

RESULTS

The ML algorithms demonstrated area under curve (AUC) and accuracy ranging 0.79-0.97 and 50%-90%, respectively on the train set. The best models were Gradient Boosting Classifier (AUC: 0.95, accuracy: 90%) and CatBoost Classifier (AUC: 0.97, accuracy: 85%). On the test set; the Voting Classifier of these two models demonstrated AUC, accuracy, recall, precision, and F1 scores as follows; 0.93, 79%, 86%, 67%, and 75%, respectively.

CONCLUSION

ML-based Computed Tomography radiomics of UC can predict HV, a prognostic factor that is indeterminable by qualitative radiological evaluation and can be missed in the preoperative histopathological specimens.

Neoadjuvant and Adjuvant Chemotherapy for Variant Histology Bladder Cancers: A Systematic Review and Meta-Analysis

Context

To improve the prognosis of variant histology (VH) bladder cancers, clinicians have used neoadjuvant chemotherapy (NAC) or adjuvant chemotherapy (AC) on the basis of radical cystectomy (RC). Despite some new data, the evidence remains mixed on their efficacy.

Objective

To update the current evidence on the role of NAC and AC for VH bladder cancers.

Evidence Acquisition

We searched for all studies investigating NAC or AC for bladder cancer patients with variant histology in PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to December 2021. The primary end points were recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS).

Evidence Synthesis

We identified 18 reports comprising a total of 10,192 patients in the NAC studies. In patients with VH, the use of NAC did improve CSS (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.55–0.99, p = 0.044), and OS (HR 0.74, 95% CI 0.66–0.84, p = 0.000), but not RFS (HR 1.15, 95% CI 0.56–2.33, p = 0.706). Subgroup analyses demonstrated that receiving NAC was associated with better OS in sarcomatoid VH (HR 0.67, 95% CI 0.54–0.83, p = 0.000) and neuroendocrine VH (HR 0.54, 95% CI 0.43–0.68, p = 0.000). For AC, we identified eight reports comprising a total of 3254 patients. There was a benefit in CSS (HR 0.61, 95% CI 0.43–0.87, p = 0.006) and OS (HR 0.76, 95% CI 0.60–0.98, p = 0.032). Subgroup analyses demonstrated that only neuroendocrine VH had better CSS (HR 0.29, 95% CI 0.13–0.67, p = 0.174) when receiving AC.

Conclusions

NAC or AC for VH bladder cancers confers an OS and CSS benefit compared with RC alone. For NAC, the benefit was independently observed in the sarcomatoid and neuroendocrine subgroups. As for AC, only neuroendocrine subgroups improved CSS.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021289487.

Variant histologies of urothelial carcinoma: Does it change the survival outcomes in patients managed with radical cystectomy?

OBJECTIVE

To investigate the impact of variant histologies (VH) of urothelial carcinoma (UC) on survival outcomes after radical cystectomy (RC).

MATERIALS AND METHODS

Data from 181 patients with UC treated with RC between January 2013 and December 2019 at a single tertiary care referral center were retrospectively accessed. All RC specimens were assigned by genitourinary dedicated pathologists. Overall survival (OS), disease-specific survival (DSS) and recurrence-free survival (RFS) were evaluated using the Kaplan-Meier methodology and the Cox proportional hazards regression.

RESULTS

Of 181 patients, 43.1% (n = 78) had VH, with the most common being squamous differentiation (n = 29), followed by mixed variants (n = 18), micropapillary variant (n = 10) and other subtypes (n = 21). The median (range) follow-up was 35 (18-59) months. Kaplan-Meier survival analysis shows that median OS and DS were significantly worse for VH patients (78 vs 31 months, p = 0.038; not reached vs 42 months; p = 0.016). At 5 years, VH was associated with a 12% and 14% decrease in OS and DSS, respectively. No significant statistical difference between the two groups was reached regarding RFS. However, after adjusting for confounders, such as, demographics characteristics, comorbidities and pathological features, VH were not associated with any survival outcomes.

CONCLUSIONS

Our study evidenced the high incidence of bladder cancers with VH. Although clearly associated with features of more aggressive behavior, VH had not any significant impact in survival expectancies when all confounders are adjusted in multivariate analyses.

Survival of Patients With UrAC and Primary BAC and Urothelial Carcinoma With Glandular Differentiation

Purpose

To investigate the significance of demographic and pathological characteristics on the survival outcomes of urachal adenocarcinoma (UrAC), primary bladder adenocarcinoma (BAC) and urothelial carcinoma with glandular differentiation (UCGD) in China.

Materials and Methods

We retrospectively analyzed cases with non-distant metastases (≤ T4M0). Of 106 patients, 30 (28.3%), 40 (37.7%), and 36 (34.0%) met the criteria for UrAC, primary BAC, and UCGD, respectively. Data on patient demographics, tumor pathology, and survival outcomes were collected. The median follow-up was 36 months. Survival was analyzed using multivariate Cox regression.

Results

Patients with UrAC were younger (51.87 ± 15.25 years) than those with primary BAC (60.50 ± 12.56 years) and UCGD (63.83 ± 11.60 years) (P<0.001). Patients with UrAC were the most likely to be stage T3–4 (70.0% vs. 40.0% vs. 44.4%; P<0.001), while the primary BAC group had a higher rate of poor differentiation than the UrAC and UCGD groups (57.4% vs. 18.5% vs. 24.1%; P<0.001). The Kaplan–Meier curves showed that the overall survival (OS), progression-free survival (PFS), and disease-specific survival (DSS) of the primary BAC group were poorer than those of both the UrAC and UCGD groups (P=0.0046,P<0.0001,P=0.0077 respectively). Regarding BAC, patients with mucinous adenocarcinoma tended to have better OS and PFS than those with other histological types (P<0.005,P=0.0245). Multivariate Cox regression analysis revealed that tumor type (P=0.002), T stage (P=0.034), and the age-adjusted Charlson Comorbidity Index (aCCI) scores (P=0.005) predicted the postoperative OS and DSS of the patients. For PFS, the tumor type (P=0.011), grade (P=0.000), and aCCI (P=0.002) scores were predictive.

Conclusion

Among UrAC, primary BAC, and UCGD patients, the prognosis was poorest for those with primary BAC. Attempts should be made to diagnose these aggressive tumors early, since patients in whom tumors are detected early appear to survive longer.

Clinically undetected plasmacytoid urothelial carcinoma of the urinary bladder with non-mass-forming metastases in multiple organs: an autopsy case

This case report outlines a clinically undetected urinary bladder plasmacytoid urothelial carcinoma (PUC) with multiple metastases detected at autopsy. An 89-year-old man presented with edema in the lower limbs. Pleural fluid cytology revealed discohesive carcinomatous cells, although imaging studies failed to identify the primary site of tumor. The patient died of respiratory failure. Autopsy disclosed a prostate tumor and diffusely thickened urinary bladder and rectum without distinct tumorous lesions. Histologically, the tumor consisted of acinar-type prostate adenocarcinoma with no signs of metastasis. Additionally, small, plasmacytoid tumor cells were observed in the urinary bladder/rectum as isolated or small clustering fashions. These metastasized to the lungs, intestine, generalized lymph nodes in a non-mass-forming manner. Combined with immunohistochemical studies, these tumor cells were diagnosed PUC derived from the urinary bladder. Both clinicians and pathologists should recognize PUC as an aggressive histological variant, which can represent a rapid systemic progression without mass-forming lesions.

T1 bladder carcinoma with variant histology: pathological features and clinical significance

The aim of the study was to stratify high-grade T1 (HGT1) bladder urothelial carcinoma into risk categories based on the presence of variant histology when compared to conventional urothelial carcinoma. The clinicopathological features of 104 HGT1 cases of urothelial carcinoma of the bladder with variant histology present in 34 (37%) were assessed. The endpoint of the study was disease-free survival and cancer-specific survival. Overall, variant histology was identified as a significant predictor of disease-free survival (P = 0.035). The presence of any specific variant histology (squamous, glandular, micropapillary, nested, microcystic, inverted growth, villous-like, basaloid, and lymphoepithelioma-like) was identified as a significant predictor of disease-free survival (P = 0.008) and cancer-specific survival (P = 0.0001) in HGT1 bladder cancer. Therefore, our results support including micropapillary HGT1 urothelial carcinoma within the aggressive high-risk category, as suggested by some recent clinical guidelines, but also favor nested, glandular, and basaloid to be placed in the high-risk category due to their potential of aggressive, life-threatening behavior and their limited response to bacillus Calmette-Guerin therapy. Conversely, the low-risk category would include urothelial carcinomas with squamous, inverted growth, or microcystic morphology, all with limited life-threatening potential and good response to current therapy. A very low-risk category would finally include patients whose tumors present villous-like or lymphoepithelioma-like morphology. In conclusion, our findings support the value of reporting the variant histology as a feature of variable aggressiveness in HGT1 urothelial carcinoma of the bladder.

Plasmacytoid variant urothelial carcinoma of the bladder: effect of radical cystectomy and chemotherapy in non-metastatic and metastatic patients

PURPOSE

Data about optimal management of plasmacytoid (PCV) bladder cancer patients are extremely scarce and limited by sample size. We focused on PCV bladder cancer patients to explore the effect of radical cystectomy (RC) and chemotherapy in non-metastatic (T _2-4N_0-3M₀), as well as in metastatic (T_anyN_anyM₁) subgroups.

METHODS

Using the Surveillance, Epidemiology and End Results database (2000-2016), we identified 332 PCV patients with muscle-invasive disease or higher (≥ T₂N₀M₀). Kaplan-Meier plots and Cox regression models addressed cancer-specific mortality (CSM).

RESULTS

In 332 PCV patients, median age was 68 years (Interquartile range [IQR]:58-76). Of those, 252 were non-metastatic patients (76%) vs 80 were metastatic patients (24%), at presentation. Of non-metastatic patients, 142 (56%) underwent RC and 131 (52%) underwent chemotherapy. Chemotherapy did not improve CSM in non-metastatic PCV. Conversely, RC was associated with lower CSM (hazard ratio [HR]: 0.51, p = 0.002). Median CSM-free survival was 48 vs 38 months for RC treated vs RC not treated. Of metastatic patients, 22 (28%) underwent RC and 42 (52%) underwent chemotherapy. Both chemotherapy and RC improved CSM in metastatic PCV. Median CSM-free survival was 12 vs 7 months for RC treated vs RC not treated (HR: 0.27, p < 0.001). Median CSM-free survival was 11 vs 4 months for chemotherapy exposed vs chemotherapy naïve (HR: 0.32, p = 0.002).

CONCLUSIONS

Although RC resulted in lower CSM, chemotherapy failed to show that effect in non-metastatic PCV patients. Conversely, both chemotherapy and RC resulted in statistically significantly lower CSM in metastatic PCV patients.

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.

Evaluation of the Extent of Variant Histology in Urothelial Carcinoma as a Predictive Marker of Clinical Outcomes After Radical Cystectomy

BACKGROUND/AIM

This study investigated the impact of the extent of variant histology (VH) on the prognosis of patients with bladder cancer (BC).

PATIENTS AND METHODS

We retrospectively evaluated consecutive patients with muscle-invasive BC who were treated with radical cystectomy (RC) at our institution between 2005 and 2018. Recurrence-free survival (RFS) and overall survival (OS) rates were evaluated using Kaplan-Meier analysis and Cox regression.

RESULTS

We identified 103 and 47 patients with pure urothelial carcinoma (UC) and a VH in UC, respectively. At the cutoff of 80%, univariate analysis identified significant differences in RFS (p=0.046) and OS (p=0.038) between patients with ≥80% VH (n=21) and those with <80% VH (n=26). Multivariate analysis revealed that the presence of ≥80% VH was significantly associated with RFS and OS.

CONCLUSION

The presence of ≥80% VH in UC could be an independent predictor of recurrence and mortality after RC.

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.

The optimal management of variant histology in muscle invasive bladder cancer

Bladder cancer is a heterogenous disease that is associated with tangible mortality in muscle invasive disease. The WHO 2016 classification of urothelial tumours reflects the contemporary approach towards histological variants in bladder cancer, including variants of urothelial carcinoma (UC) and non-urothelial variants. This review focuses on variant histology in UC, and discusses the importance of accurate histological diagnosis, and subsequent risk stratification and therapeutic decision making based on proper variant recognition. Most urothelial variants are associated with poorer outcomes compared to conventional UC, although some perform reasonably better. However, high quality evidence detailing optimal treatment and survival outcomes are still lacking in literature, due to the rarity of these cases.

Sarcomatoid variant urothelial carcinoma of the bladder: a systematic review and meta-analysis of the clinicopathological features and survival outcomes

Background

A systematic review and meta-analysis was performed to compare the clinicopathological features and survival outcomes between sarcomatoid variant (SV)-urothelial carcinoma of the bladder (UCB) and conventional UCB (C-UCB).

Methods

A comprehensive search of PubMed, Embase, and Cochrane Library was performed. Endpoints included clinicopathological features and survival outcomes (overall survival [OS], cancer-specific survival [CSS], and progression-free survival [PFS]). The survival benefits of neoadjuvant chemotherapy (NAC) or adjuvant chemotherapy (AC) for SV-UCB also have been studied.

Results

A total of 8 observational studies were included. Patients with SV-UCB had a higher rate of ≥ stage pT3 (odds ratio [OR], 2.06; 95% confidence interval [CI], 1.64–2.59; p < 0.001) and a lower rate of concomitant carcinoma in situ (OR, 0.25; 95% CI, 0.09–0.72; p = 0.010). The other clinicopathological variables were similar between SV-UCB and C-UCB. With unadjusted data, patients with SV-UCB had a significant inferior OS (HR, 1.24; 95% CI, 1.07–1.44; p = 0.004) and CSS (HR, 2.08; 95% CI, 1.63–2.66; p < 0.001). However, after adjusted, SV-UCB had worse OS (HR, 1.41; 95% CI, 0.95–2.08; p = 0.090) and CSS (HR, 1.54; 95% CI, 0.95–2.52; p = 0.080) approaching the borderline of significance. For SV-UCB, NAC (HR, 0.73; 95% CI, 0.51–1.05; p = 0.090) and AC (HR, 0.88; 95% CI, 0.66–1.17; p = 0.370) seemed to have no benefit on OS.

Conclusions

Compared to C-UCB, SV-UCB was associated with more advanced disease and more inferior OS and CSS. NAC and AC had no survival benefit for SV-UCB.

Neoadjuvant therapy for muscle-invasive bladder cancer

INTRODUCTION

Muscle-invasive bladder cancer (MIBC) is generally a highly aggressive malignancy with early and mostly distant recurrences. Cisplatin-based combinations have been established as neoadjuvant chemotherapy (NAC) prior to radical cystectomy (RC) providing overall survival as well as disease-free survival benefit. Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of metastatic urothelial carcinoma and are being tested in the neoadjuvant setting as well.

AREAS COVERED

This review covers the existing guidelines for the management of MIBC. It summarizes the use of different NAC regimens. It also discusses the published literature of ICIs in this setting and explores future perspectives.

EXPERT OPINION

Cisplatin-based NAC is the standard of care in MIBC prior to RC. Cisplatin-ineligible MIBC patients have not demonstrated to clearly benefit from a chemotherapy regimen and proceed directly to RC, although novel agents have been evaluated in this setting. Pembrolizumab and atezolizumab as monotherapy have shown feasibility and promising pathologic response rates. The combination of cisplatin-based chemotherapy with ICIs and chemotherapy-free ICI alone approaches are being investigated in randomized trials. Molecular subclassification and development of predictive biomarkers in MIBC will further help to identify optimal treatment strategies in these patients.

Role of Neoadjuvant Chemotherapy in Squamous Variant Histology in Urothelial Bladder Cancer: Does Presence and Percentage Matter?

BACKGROUND

The purpose of this study was to evaluate the effect of neoadjuvant chemotherapy (NACT) on squamous variant (SV) bladder cancer by investigating patients presenting with SV histology at the time of transurethral resection (TUR), stratified by their receipt of NACT.

MATERIALS AND METHODS

The records of 71 patients with muscle-invasive bladder cancer and SV in the TUR specimen who underwent cystectomy between 2008 and 2018 were reviewed. Our primary outcome was pathologic response at time of cystectomy. Secondary outcomes included recurrence-free survival and overall survival stratified by receipt of NACT. A subgroup analysis was then conducted on the patients with defined SV% on TUR stratified by % involvement (< 50% SV vs. ≥ 50% SV).

RESULTS

The median age of the NACT and no-NACT groups was 60.2 and 70 years, respectively (P = .003). The complete response rate at cystectomy was 60% versus 13.7% for the NACT and no-NACT groups, respectively (P < .001). The non-organ-confined disease rate at time of radical cystectomy was 35% for the NACT group and 68.6% for the no-NACT group (P = .01). The NACT group had fewer recurrences than the no-NACT group (10% vs 47.1%; P = .003). In the subgroup analysis, the lower rate of non-organ-confined disease persisted for the patients who underwent NACT at the lower SV percentage but failed to remain significant at greater percentage involvement. This was also true for overall survival.

CONCLUSIONS

The effect of NACT in variant histology bladder cancer is variable. In patients with SV, these results favor the recommendation in favor of NACT administration, particularly when the primary tumor has < 50% involvement by the variant histology.

Adherence to guideline recommendations for multimodality treatment of patients with pT2-3 M0 non-urothelial carcinoma of the urinary bladder: Temporal trends and survival outcomes

OBJECTIVES

To analyze contemporary multimodality treatment rates, defined as radical cystectomy plus chemotherapy and/or radiotherapy, for pT2-3 any N-stage M0 non-urothelial carcinoma of urinary bladder patients. Additionally, we tested for the effect of multimodality treatment versus radical cystectomy alone on cancer-specific mortality.

METHODS

Within the Surveillance, Epidemiology and End Results database (2004-2015), 887 pT2-3 any N-stage M0 non-urothelial carcinoma of urinary bladder patients treated with radical cystectomy were identified. Kaplan-Meier plots, and univariable and multivariable Cox regression analyses focused on cancer-specific mortality rates.

RESULTS

Squamous cell carcinoma was recorded in 499 (56.3%) patients, neuroendocrine carcinoma in 246 (27.7%) and adenocarcinoma in 142 (16.0%). The highest proportion of multimodality treatment patients was recorded in neuroendocrine carcinoma (69.1%), relative to adenocarcinoma (34.5%) and squamous cell carcinoma (26.4%). A statistically significant annual increase was recorded in multimodality treatment rates in neuroendocrine carcinoma patients (46.7-74.2%, P < 0.01), but not in adenocarcinoma or squamous cell carcinoma patients. The 5-year cancer-specific mortality rate in neuroendocrine carcinoma patients was significantly lower after multimodality treatment versus radical cystectomy alone (37.0% vs 51.5%; P < 0.01), but no statistically significant differences were recorded in both adenocarcinoma (46.1% vs 35.5%; P = 0.8) and squamous cell carcinoma (41.4% vs 31.1%; P = 0.8) patients. In multivariable analyses, for neuroendocrine carcinoma patients, multimodality treatment was an independent predictor of a lower cancer-specific mortality rate (hazard ratio 0.58, P = 0.03).

CONCLUSIONS

Multimodality treatment has been increasingly used during the study period in neuroendocrine carcinoma patients, and it has translated into a cancer-specific mortality benefit. This is not the case for other non-urothelial carcinoma of urinary bladder patients, such as adenocarcinoma or squamous cell carcinoma.

EAU-ESMO Consensus Statements on the Management of Advanced and Variant Bladder Cancer-An International Collaborative Multistakeholder Effort†: Under the Auspices of the EAU-ESMO Guidelines Committees

BACKGROUND

Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.

OBJECTIVE

To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.

DESIGN

A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts prior to voting during a consensus conference.

SETTING

Online Delphi survey and consensus conference.

PARTICIPANTS

The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), and 7-9 (agree). A priori (level 1) consensus was defined as ≥70% agreement and ≤15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).

RESULTS AND LIMITATIONS

Overall, 116 statements were included in the Delphi survey. Of these statements, 33 (28%) achieved level 1 consensus and 49 (42%) achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease, and the evolving role of checkpoint inhibitor therapy in metastatic disease.

CONCLUSIONS

These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time when further evidence is available to guide our approach.

PATIENT SUMMARY

This report summarises findings from an international, multistakeholder project organised by the EAU and ESMO. In this project, a steering committee identified areas of bladder cancer management where there is currently no good-quality evidence to guide treatment decisions. From this, they developed a series of proposed statements, 71 of which achieved consensus by a large group of experts in the field of bladder cancer. It is anticipated that these statements will provide further guidance to health care professionals and could help improve patient outcomes until a time when good-quality evidence is available.

Naturally-Occurring Invasive Urothelial Carcinoma in Dogs, a Unique Model to Drive Advances in Managing Muscle Invasive Bladder Cancer in Humans

There is a great need to improve the outlook for people facing urinary bladder cancer, especially for patients with invasive urothelial carcinoma (InvUC) which is lethal in 50% of cases. Improved outcomes for patients with InvUC could come from advances on several fronts including emerging immunotherapies, targeted therapies, and new drug combinations; selection of patients most likely to respond to a given treatment based on molecular subtypes, immune signatures, and other characteristics; and prevention, early detection, and early intervention. Progress on all of these fronts will require clinically relevant animal models for translational research. The animal model(s) should possess key features that drive success or failure of cancer drugs in humans including tumor heterogeneity, genetic-epigenetic crosstalk, immune cell responsiveness, invasive and metastatic behavior, and molecular subtypes (e.g., luminal, basal). Experimental animal models, while essential in bladder cancer research, do not possess these collective features to accurately predict outcomes in humans. These key features, however, are present in naturally-occurring InvUC in pet dogs. Canine InvUC closely mimics muscle-invasive bladder cancer in humans in cellular and molecular features, molecular subtypes, immune response patterns, biological behavior (sites and frequency of metastasis), and response to therapy. Thus, dogs can offer a highly relevant animal model to complement other models in research for new therapies for bladder cancer. Clinical treatment trials in pet dogs with InvUC are considered a win-win-win scenario; the individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to translate to better treatment outcomes in humans. In addition, the high breed-associated risk for InvUC in dogs (e.g., 20-fold increased risk in Scottish Terriers) offers an unparalleled opportunity to test new strategies in primary prevention, early detection, and early intervention. This review will provide an overview of canine InvUC, summarize the similarities (and differences) between canine and human InvUC, and provide evidence for the expanding value of this canine model in bladder cancer research.

Clinical and pathological characteristics of bladder cancer in post brachytherapy patients

The long-term risk of secondary malignancy is a potential late effect of brachytherapy. However, the time interval, anatomic site and histopathology are not well studied. We sought to characterize the bladder cancers that developed following treatment of prostate cancer with brachytherapy. Between 1998 and 2014, 4570 patients were treated with brachytherapy at the BC Cancer Agency. Out of those, 69 patients subsequently developed bladder cancer, some of which could have been radiation induced. Histology slides were reviewed for all cases, and site and pathologic features were recorded. Cases were classified as luminal and basal subtypes based on GATA3 and CK5/6 immunohistochemistry. Bladder neck and trigone were among the common sites of involvement. Pathologic review of cases showed that 68 % were high-grade, 25 % were muscle-invasive, and 20 % showed variant histology, including small cell carcinoma, sarcomatoid carcinoma, squamous cell carcinoma, and adenocarcinoma. A subgroup of cases more likely to be radiation-induced, based on site and time interval, was associated with increased pathologic stage (pT1 or higher) compared to the other cases (70 % vs 34 %, p = 0.01). In conclusion, the majority of bladder cancers following brachytherapy in this cohort were of high grade and low stage at diagnosis, most of them demonstrating luminal immunophenotype. A significant number of variant histologies are seen, each demonstrating a specific immunophenotype.

EAU-ESMO consensus statements on the management of advanced and variant bladder cancer-an international collaborative multi-stakeholder effort: under the auspices of the EAU and ESMO Guidelines Committees†

BACKGROUND

Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.

OBJECTIVE

To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.

DESIGN

A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts before voting during a consensus conference.

SETTING

Online Delphi survey and consensus conference.

PARTICIPANTS

The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), 7-9 (agree). A priori (level 1) consensus was defined as ≥70% agreement and ≤15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).

RESULTS AND LIMITATIONS

Overall, 116 statements were included in the Delphi survey. Of these, 33 (28%) statements achieved level 1 consensus and 49 (42%) statements achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease and the evolving role of checkpoint inhibitor therapy in metastatic disease.

CONCLUSIONS

These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time where further evidence is available to guide our approach.

Survival After Partial Cystectomy for Variant Histology Bladder Cancer Compared With Urothelial Carcinoma: A Population-based Study

BACKGROUND

The present study tested cancer-specific (CSM) and overall mortality (OM) after partial cystectomy (PC) for variant histology bladder cancer (non-urothelial carcinoma of the urinary bladder UCUB), relative to UCUB and relative to radical cystectomy (RC).

MATERIALS AND METHODS

Within the Surveillance, Epidemiology, and End Results registry (2001-2016), we identified patients with stage T1-T2N0M0 non-UCUB and UCUB who had undergone PC or RC. Non-UCUB included adenocarcinoma, squamous carcinoma, neuroendocrine carcinoma, and other histologic subtypes. First, CSM and OM after PC were compared between the non-UCUB and UCUB groups. Second, CSM and OM after PC were compared with RC in the non-UCUB group. Kaplan Meier plots and multivariable Cox regression models were used before and after inverse probability of treatment weighting.

RESULTS

Overall, 248 patients (16.3%) treated with PC had had non-UCUB. Of the 248 cases, 115 (46.5%), 50 (20%), 34 (14%), and 49 (19.5%) were adenocarcinoma, squamous carcinoma, neuroendocrine carcinoma, and other histologic subtypes, respectively. The comparison between PC in the non-UCUB and PC in the UCUB group showed higher CSM (hazard ratio, 1.4; P = .03) but the same OM rates (hazard ratio, 1.1; P = .7) in the non-UCUB group. The comparison between PC and RC for the non-UCUB group showed no CSM or OM differences.

CONCLUSIONS

PC for non-UCUB was associated with higher CSM compared with PC for UCUB. However, PC instead of RC for select patients with non-UCUB appears not to undermine cancer-control outcomes. Thus, the excess CSM is probably unrelated to cystectomy type but could originate from differences in the tumor biology. These results could act as hypothesis generating for the design of future trials.

The clinicopathological characteristics and prognostic value of squamous differentiation in patients with bladder urothelial carcinoma: a meta-analysis

PURPOSE

Urothelial carcinoma with squamous differentiation (UCSD) is the most common histologic variant in bladder cancer (BCa). Previously, some studies have linked the presence of UCSD with the risk of worse survival outcomes in BCa patients. However, such association is still controversial. In this study, we performed a meta-analysis to clarify the clinicopathological characteristics and to further investigate the prognostic value of UCSD in BCa.

METHODS

A systematic literature search was performed in electronic databases including PubMed, Embase, Chinese National Knowledge Infrastructure and Wanfang Data until October 2018. Subgroup analyses were performed according to different treatments and study outcomes.

RESULTS

Total of 13,284 patients were enrolled in 19 studies which were included in this meta-analysis. The percentage of female patients with UCSD was significantly higher than those with pure urothelial carcinoma. UCSD was correlated with tumor stage T3/T4, tumor grade 3, positive surgical margin, and lymph node involvement. Moreover, the recurrence rate was higher in patients with UCSD after surgery. UCSD was associated with poorer disease-free survival (DFS). No significant difference of cancer-specific survival (CSS) or overall survival (OS) was found on multivariable analysis between the two groups.

CONCLUSIONS

Our study demonstrated that UCSD in BCa was associated not only with unfavorable clinicopathological features, but also with high risk of recurrence and poorer prognosis for DFS. However, UCSD is not independently significant for CSS and OS. Well-designed randomized study with larger sample size is warranted to verify the findings and to further explore the role of UCSD in BCa.

Clinical Significance of Squamous Differentiation in Urothelial Carcinoma of the Bladder

The prognostic value of squamous differentiation (SD) in urothelial carcinoma (UC) of the bladder is unclear. The aim of this study was to identify the clinical significance of SD in UC in terms of oncological outcomes in patients undergoing radical cystectomy (RC). We evaluated consecutive patients with muscle-invasive bladder cancer (MIBC; clinical T2-4aN0M0) treated with RC at our institution from March 2003 to March 2017. We enrolled 20 and 81 patients with UC with SD (UCSD) and pure UC, respectively. Postoperative survival outcomes were compared between the patients with UCSD and pure UC using the Kaplan-Meier method. Pre- and postcystectomy factors that influenced the overall survival (OS) and recurrence-free survival (RFS) were investigated in these patients. Multivariate Cox regression models were used to identify the predictors of OS and RFS. With a median follow-up time of 31 months, the 5-year OS rate of the UCSD and pure UC groups was 41.1% and 69.7% (P = .002) and the 5-year RFS rate was 51.8% and 59.5% (P = .027), respectively. The shape of the Kaplan-Meier curves for UCSD suggested a more rapid course of the disease within the first 2 years than observed in pure UC. Multivariate analyses suggested that SD in UC was significantly associated with OS (hazard ratio [HR]: 4.22; 95% confidence interval [CI]: 1.20-14.8; P = .024) and close to significance for a lower RFS (HR: 2.13, 95% CI: 0.74-6.15, P = .064). Our results indicate that SD may be an independent predictor of OS and RFS in UC of MIBC in patients undergoing RC.

Bacillus Calmette-Guérin may have clinical benefit for glandular or squamous differentiation in non-muscle invasive bladder cancer patients: retrospective multicenter study

Objectives

To clarify the efficacy of intravesical Bacillus Calmette-Guérin (BCG) instillation for non-muscle invasive bladder (NMIBC) cancer with variant histology, especially glandular differentiation or squamous differentiation.

Materials and methods

From May 1991 through June 2016, 53 patients were diagnosed retrospectively as having NMIBC with variant histology. Among these patients, 47 NMIBC patients with squamous differentiation or glandular differentiation were analyzed for this study. The median follow-up interval from diagnosis of NMIBC with variant histology was 28.9 months (1.5-168.8).

Results

Of these patients, 38 (80.9%) and 9 (19.1%) were diagnosed as having glandular differentiation and squamous differentiation, respectively. Radical cystectomy was conducted for six (12.8%) immediately after the diagnosis of NMIBC with variant histology. Of the 41 patients with bladder preservation, 20 (48.8%), 3 (7.3%), 3 (7.3%) and 15 (36.6%) underwent BCG, THP, MMC and no additional treatment, respectively. There were significant differences between BCG and other treatments or no additional treatment for recurrence (P = 0.034), progression (P = 0.004) and cancer-specific survival (P = 0.014).

Conclusion

Overall, our results show that intravesical BCG instillation for variant histology in NMIBC leads to a better prognosis with regard to progression and cause-specific survival than other intravesical treatments or no additional treatment. BCG treatment may also have a clinical benefit for variant histology in non-muscle invasive bladder cancer patients.

Do histological variants in urothelial carcinoma of the bladder portend poor prognosis? A systematic review and meta-analysis

The clinical implications of histological variants in urothelial carcinoma of the bladder has been a subject of significant controversy with many unanswered questions that remain. To clarify whether histological variants presage poor prognosis for patients suffering from urothelial carcinoma of the bladder, we scoured through various electronic databases such as Medline, Web of Knowledge, and the Cochrane Library up to August 18, 2016. Experts were consulted, and references from relevant articles were scanned. We identified thirteen eligible studies which met the inclusion criteria, including 9,533 participants. The existing evidence indicates that histological variants in urothelial carcinoma of the bladder patients do not alter their prognosis.