Overview of histologic variants of urothelial carcinoma: current trends and narrative review on treatment outcomes

Incidence trends, histological subtypes, and topographical distribution of bladder cancer in Iran: a study based on the Iranian National Cancer Registry during 2006-2015

Background

Bladder cancer (BCa) is a significant public health concern. This study aimed to analyze the incidence trends, histological subtypes, and topographical distribution of BCa in Iran over a decade.

Methods

This retrospective registry-based study analyzed data on BCa patients diagnosed between March 20, 2006, and March 20, 2015. Following data quality control, age-standardized incidence rates (ASIRs) were calculated for BCa overall, by sex and histological subtype using the new World Health Organization (WHO) standard population.

Results

We identified 51,379 BCa cases (81.97% male) with a mean age of 65.10 ± 14.89 years. The overall ASIR was 8.92 per 100,000 (95% CI: 8.84-9.00). While a modest increase in ASIR was observed overall (8.77 in 2006 to 9.64 in 2015) and among males (14.13 in 2006 to 15.95 in 2015) during the study period, males consistently had a significantly higher ASIR compared to females (approximately 4.5:1 ratio). BCa incidence showed a progressive increase across older age groups, particularly those aged 40-44 to 80-84 years. Urothelial cell carcinoma (UCC) was the most prevalent histological type (ASIR: 8.19 to 7.93), followed by adenocarcinoma (AC; ASIR: 0.13 to 0.11). Squamous cell carcinoma (SCC) displayed a decreasing trend (ASIR: 0.11 to 0.06). Both UCC and AC were more frequent in males (approximately 5 and 3 times higher than females, respectively). Malignant neoplasm of the bladder, unspecified, constituted over 95% of BCa topography classifications.

Conclusion

This study identified a modest rise in BCa incidence, with male predominance and a higher burden in older adults. Further investigation into potential risk factors contributing to this increase is warranted.

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.

Pictorial review of multiparametric MRI in bladder urothelial carcinoma with variant histology: pearls and pitfalls

Bladder cancer (BC), predominantly comprising urothelial carcinomas (UCs), ranks as the tenth most common cancer worldwide. UCs with variant histology (variant UC), including squamous differentiation, glandular differentiation, plasmacytoid variant, micropapillary variant, sarcomatoid variant, and nested variant, accounting for 5-10% of cases, exhibit more aggressive and advanced tumor characteristics compared to pure UC. The Vesical Imaging-Reporting and Data System (VI-RADS), established in 2018, provides guidelines for the preoperative evaluation of muscle-invasive bladder cancer (MIBC) using multiparametric magnetic resonance imaging (mpMRI). This technique integrates T2-weighted imaging (T2WI), dynamic contrast-enhanced (DCE)-MRI, and diffusion-weighted imaging (DWI) to distinguish MIBC from non-muscle-invasive bladder cancer (NMIBC). VI-RADS has demonstrated high diagnostic performance in differentiating these two categories for pure UC. However, its accuracy in detecting muscle invasion in variant UCs is currently under investigation. These variant UCs are associated with a higher likelihood of disease recurrence and require precise preoperative assessment and immediate surgical intervention. This review highlights the potential value of mpMRI for different variant UCs and explores the clinical implications and prospects of VI-RADS in managing these patients, emphasizing the need for careful interpretation of mpMRI examinations including DCE-MRI, particularly given the heterogeneity and aggressive nature of variant UCs. Additionally, the review addresses the fundamental MRI reading procedures, discusses potential causes of diagnostic errors, and considers future directions in the use of artificial intelligence and radiomics to further optimize the bladder MRI protocol.

Clinicohistopathological Correlation and Prognostic Significance of Molecular Biomarkers in Urinary Bladder Neoplasms: A Comprehensive Analysis

BACKGROUND

Urinary bladder neoplasms constitute a heterogeneous group of tumors with diverse clinical behaviors and outcomes. Understanding the correlation between clinicopathological characteristics and the prognostic significance of molecular biomarkers in bladder cancer is vital for personalized treatment strategies and improved patient outcomes.

OBJECTIVE

This prospective observational study aimed to comprehensively investigate the clinicopathological correlations and prognostic significance of molecular biomarkers in urinary bladder neoplasms.

METHODS

A cohort of 174 patients diagnosed with urinary bladder neoplasm participated in this study. Clinicopathological data, including demographic information, medical history, imaging findings, and histopathological reports, were collected from the patient records. Tissue samples obtained from transurethral resection or biopsy were subjected to molecular biomarker analysis using immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and molecular profiling techniques. Longitudinal follow-up assessments were conducted to monitor disease progression, recurrence, and overall survival.

RESULT

Out of 174 patients diagnosed with bladder neoplasms, the mean age of the patients was 62.4 years (±8.7), indicating that the study cohort primarily comprised elderly individuals. The majority of patients were male (126, 72.4%), reflecting the higher prevalence of bladder cancer among men compared to women. Preliminary analysis revealed significant associations between clinicopathological parameters, molecular biomarker expression profiles, and clinical outcomes in patients with urinary bladder neoplasms. Elevated expression levels of specific biomarkers such as tumor protein p53 (p53), Ki-67, and estimated glomerular filtration rate (EGFR) were observed in advanced tumor stages (p < 0.001) and higher histological grades (p < 0.05), indicating their potential prognostic significance. Furthermore, genetic alterations detected using molecular profiling techniques, including chromosomal gains and losses, were significantly correlated with aggressive disease phenotypes and increased recurrence risk (p < 0.01). Longitudinal follow-up data demonstrated that patients with elevated biomarker expression levels or genetic alterations had poorer treatment responses and shorter overall survival durations than those with lower biomarker expression levels.

CONCLUSION

This study highlights the importance of integrating clinicopathological parameters and molecular biomarker data for the risk stratification, treatment selection, and prognostic assessment of urinary bladder neoplasms.

Adjuvant Chemotherapy after Radical Nephroureterectomy for Upper Tract Urothelial Carcinoma with Variant Histology: A Systematic Review and Meta-Analysis of Survival Outcomes

INTRODUCTION

The objective of this study was to determine effects of adjuvant chemotherapy (AC) on survival outcomes compared to surgery alone without AC for upper tract urothelial carcinoma (UTUC) patients with variant histology (VH).

METHODS

We conducted a systematic review and meta-analysis of studies investigating AC for UTUC in Medline, Embase, the Cochrane Library up to January 2023. Population, intervention, comparator, and outcome were UTUC patients with VH, radical nephroureterectomy with AC, radical nephroureterectomy only, and oncological survival, respectively.

RESULTS

Four retrospective studies were included. Regarding overall survival (OS), the pooled hazard ratio was 0.61 (95% confidence interval: 0.42-0.87; p = 0.007) across two studies. Regarding cancer-specific survival (CSS), the pooled hazard ratio was 0.46 (95% confidence interval: 0.25-0.84; p = 0.01) across three studies. All included studies had a high quality based on the Newcastle-Ottawa Scale. Certainty of evidence for OS was low. Certainty of evidence for CSS was moderate due to a strong association (hazard ratio <0.5). Publication bias was not significant for any studies.

CONCLUSION

In UTUC patients with VH, administration of AC after surgery might have better survival outcomes than surgery alone. Our study provides evidence for decision-making of clinicians who treat UTUC patients with VH.

Glycocalyx analysis of bladder cancer: three-dimensional images in electron microscopy and vicia villosa lectin as a marker for invasiveness in frozen sections

Introduction: The abnormal glycocalyx (GCX) on the surface of cancer cells has been reported to be tall and aberrantly glycosylated and has been linked to the progression and spread of cancer-a finding also observed in bladder cancer. However, the characteristics of GCX in various types of human bladder cancer remain unknown, and herein, we aimed to provide information on the diversity of glycan components in the GCX of bladder cancers and to shed light on their characteristics. Methods: We used scanning electron microscopy and lanthanum staining to examine the surface GCX of human bladder carcinomas in three-dimensional images, showing the bulky GCX in some carcinomas. We also examined glycan alterations in early to progressive stages of bladder cancers using 20 distinct lectin stains on frozen sections from transurethral resection of bladder tumors. Results and discussion: Distinctive Vicia villosa lectin (VVL) staining was observed in invasive urothelial carcinomas, including those with muscle invasion and variant components. In the clinical setting, cancers with atypia of grades 2-3 had a significantly higher VVL scoring intensity than those with grade 1 atypia (p < 0.005). This study identified that a specific lectin, VVL, was more specific to invasive urothelial carcinomas. This lectin, which selectively binds to sites of cancer progression, is a promising target for drug delivery in future clinical investigations.

The perioperative and long-term outcomes of patients with variant histology bladder cancer undergoing radical cystectomy: A propensity score-matched analysis with pure urothelial carcinoma

OBJECTIVES

To assess the perioperative and long-term outcomes after open radical cystectomy in patients with histological variants versus pure urothelial carcinoma.

METHODS

Patients with a variant histology carcinoma of the urinary bladder were matched through a propensity score analysis with those with pure urothelial carcinoma on a 1:3 ratio. The two groups were compared in terms of perioperative and long-term morbidity and mortality.

RESULTS

Overall, 148 individuals were included in the present retrospective study (37 with variant histology and 111 with pure urothelial carcinoma). A total of 107 (72.3%) individuals presented at least one perioperative complication based on the Clavien-Dindo classification. This proportion was similar between patients with urothelial versus variant histology carcinoma (P = .22). In the long term, the number of patients with clinically significant incisional hernia requiring surgery [14 (12.7%) vs 3 (8.3%), P = .68], uretero-intestinal/uretero-cutaneous strictures or any other complication related to the applied urinary diversion [15 (13.6%) vs 7 (19.4%), P = .56], as well as the number of patients presenting with septicemia [17 (15.5%) vs 10 (27.8%), P = .16] or with urinary tract obstruction [12 (10.9%) vs 4 (11.1%), P > .99] at follow-up did not differ between urothelial versus variant histology carcinoma. The survival analysis with Kaplan-Meier curves and the univariate Cox regression model suggested that the risk of death from any cause was increased in patients with variant compared to pure urothelial histology (log-rank test = 0.045, hazard ratio: 1.7, 95% confidence interval: 1.01-2.87, P = .047).

CONCLUSIONS

Perioperative morbidity and mortality are comparable in patients with variant histology versus pure urothelial carcinoma.

Do Histology and Primary Tumor Location Influence Metastatic Patterns in Bladder Cancer?

Metastasis is the leading cause of death in patients with bladder cancer. This study utilized a statistical analysis of patient data from the Surveillance, Epidemiology, and End Results database to examine the influence of histological type and primary site on the metastatic behavior of bladder cancer. Significantly different metastatic patterns were observed among bladder cancer patients depending on their histological type. Patients with squamous cell carcinoma showed a significantly (p < 0.001) lower bone metastasis rate (27.2%) than patients with urothelial carcinoma (UC) (38.3%). Patients with neuroendocrine carcinoma showed a significantly (p < 0.001) higher liver metastasis rate (52.1%) and a significantly (p = 0.001) lower lung metastasis rate (25.7%) than patients with UC (22.6% and 33.5%, respectively). UC patients also demonstrated differences in metastatic behavior according to histological subtype. The sarcomatoid subtype showed a significantly (p < 0.001) higher lung metastasis rate (51.6%) and a significantly lower (p = 0.002) lymph node metastasis rate (22.6%) than the micropapillary subtype (12.1% and 54.1%, respectively). Significant differences in metastatic behavior were also observed among patients with conventional UCs originating from the bladder, ureter, and renal pelvis. This study highlights the impact of histological characteristics and primary site on metastatic tendencies in bladder cancer, highlighting the importance of tailoring treatment and surveillance strategies.

A nested variant of urothelial carcinoma of the urethra and urinary bladder: A case report and review of literature

Nested variant of urothelial carcinoma (NV-UC) is an extremely rare cancer with a nonspecific presentation. It is usually identified at a late stage, which makes the treatment challenging. Herein we report the case of a 52-year-old woman with an advanced NV-UC treated by anterior exenteration after a poor response to neoadjuvant chemotherapy. One year after completion of adjuvant radiotherapy, the patient remains disease-free.

PI3K/AKT/mTOR Dysregulation and Reprogramming Metabolic Pathways in Renal Cancer: Crosstalk with the VHL/HIF Axis

Renal cell carcinoma (RCC) represents 85-95% of kidney cancers and is the most frequent type of renal cancer in adult patients. It accounts for 3% of all cancer cases and is in 7th place among the most frequent histological types of cancer. Clear cell renal cell carcinoma (ccRCC), accounts for 75% of RCCs and has the most kidney cancer-related deaths. One-third of the patients with ccRCC develop metastases. Renal cancer presents cellular alterations in sugars, lipids, amino acids, and nucleic acid metabolism. RCC is characterized by several metabolic dysregulations including oxygen sensing (VHL/HIF pathway), glucose transporters (GLUT 1 and GLUT 4) energy sensing, and energy nutrient sensing cascade. Metabolic reprogramming represents an important characteristic of the cancer cells to survive in nutrient and oxygen-deprived environments, to proliferate and metastasize in different body sites. The phosphoinositide 3-kinase-AKT-mammalian target of the rapamycin (PI3K/AKT/mTOR) signaling pathway is usually dysregulated in various cancer types including renal cancer. This molecular pathway is frequently correlated with tumor growth and survival. The main aim of this review is to present renal cancer types, dysregulation of PI3K/AKT/mTOR signaling pathway members, crosstalk with VHL/HIF axis, and carbohydrates, lipids, and amino acid alterations.