The impact of grading scheme on non-muscle invasive bladder cancer progression: potential utility of hybrid grading schemes

Head-to-head: how many categories for grading urothelial carcinoma?

Tumour grade is a critical prognostic parameter for guiding the management of patients with non-muscle invasive bladder cancer. In 2004, the World Health Organisation (WHO) adopted a binary (low-grade/high-grade) grading system to replace the three-tier (grades 1-3) system used to grade urothelial carcinoma since 1973. However, there is significant global variation in the grading of urothelial carcinoma. Some pathology and clinical guidelines recommend reporting of the WHO 1973 and 2004 grades in parallel, while others require reporting only of the WHO 2004 grade. This variation in pathology practice is clinically significant, because the two grading systems are not readily translatable. Some experts have proposed novel systems for grading urothelial carcinoma that involve splitting of the WHO 1973 and 2004 grade categories. The arguments for and against splitting urothelial carcinomas into two-, three- and four-grade categories are independently discussed by the three authors.

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.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 1: Comparison of Bladder Cancer Grading System Performance

Grade is a key prognostic factor in determining progression in nonmuscle invasive papillary urothelial carcinomas. The 2 most common grading methods in use worldwide are the World Health Organization (WHO) 2004 and 1973 schemes. The International Society of Urological Pathology (ISUP) organized the 2022 consensus conference in Basel, Switzerland on current issues in bladder cancer and tasked working group 1 to make recommendations for future iterations of bladder cancer grading. For this purpose, the ISUP developed in collaboration with the European Association of Urology a 10-question survey for their memberships to understand the current use of grading schemes by pathologists and urologists and to ascertain the areas of potential improvements. An additional survey was circulated to the ISUP membership for their opinion on interobserver variability in grading, reporting of urine cytology, and challenges encountered in grade assignment. Comprehensive literature reviews were performed on bladder cancer grading prognosis and interobserver variability along with The Paris System for urine cytology. There are notable differences in practice patterns between North American and European pathologists in terms of used grading scheme and diagnosis of papillary urothelial neoplasm of low malignant potential. Areas of common ground include difficulty in grade assignment, a desire to improve grading criteria, and a move towards subclassifying high-grade urothelial carcinomas. The surveys and in-person voting demonstrated a strong preference to refine current grading into a 3-tier scheme with the division of WHO 2004 high grade into clinically relevant categories. More variable opinions were voiced regarding the use of papillary urothelial carcinoma with low malignant potential.

Bladder cancer grading using the four-tier combination of the World Health Organization (WHO) 1973 and WHO 2004 classifications

OBJECTIVE

To investigate the impact of grading in urothelial bladder cancer (UBC) stages Ta and T1, comparing the World Health Organization (WHO) grading classifications of 1973 (WHO73) and 2004 (WHO04) and a combination of these (WHO73/04).

PATIENTS AND METHODS

All patients with primary Ta and T1 UBC in the Östergötland region, Sweden, between 1992 and 2007 were included. From 1992, we introduced a new programme for management and follow-up of UBC, including prospectively performed registration of all patients, a systematic description of the location and size of all tumours, primary resection and intravesical treatment in the case of recurrence. All tumour specimens were retrospectively reviewed in 2008 and graded according to the WHO73 and WHO04. A combination of WHO73/04, Grade 1 (G1), Grade 2 low grade (G2LG), Grade 2 high grade (G2HG) and Grade 3 (G3) was analysed in relation to clinical variables and outcomes.

RESULTS

There were 769 patients with a median age of 72 years and a median follow-up duration of 74 months. Recurrence was noted in 484 patients (63%) and progression in 80 patients (10%). Recurrence was more common in multiple tumours, larger tumours and in tumours of higher grade (G2LG, G2HG and G3). Progression was more common in tumours classified as larger, T1 and G2HG and G3. Notably, in tumours classified as G2HG, recurrence and progression were more common than in the G2LG group. Harrell's concordance index for the WHO73/04 was higher for recurrence and progression than in the WHO73 or WHO04.

CONCLUSION

In the four-tier combined WHO73/04 for urothelial cancer, we observed two G2 sub-groups, G2HG and G2LG. There was a better outcome in the latter group, and the importance of G1 and G3 tumours could be fully evaluated. The WHO73/04 had greater accuracy for recurrence and progression than either the WHO73 or WHO04.

CD44 is a potential immunotherapeutic target and affects macrophage infiltration leading to poor prognosis

CD44 plays a key role in the communication of CSCs with the microenvironment and the regulation of stem cell properties. UALCAN was used to analyze the expression of CD44 in bladder cancer (BLCA) and normal tissue. The UALCAN was utilized to analyze the prognostic value of CD44 in BLCA. The TIMER database was used to explore the relationship between CD44 and PD-L1; CD44 and tumor-infiltrating immune cells. The regulatory effect of CD44 on PD-L1 was verified by cell experiments in vitro. IHC confirmed the results of the bioinformatics analysis. GeneMania and Metascape were used to analyze protein-protein interaction (PPI) investigations and functional enrichment analysis. We found that BLCA patients with high CD44 expression had worse survival than those with low CD44 expression (P < 0.05). IHC and the TIMER database results showed that CD44 expression was positively correlated with PD-L1 expression (P < 0.05). At the cellular level, the expression of PD-L1 was significantly inhibited after CD44 expression was inhibited by siRNA. Immune infiltration analysis showed that CD44 expression levels in BLCA were significantly correlated with immune infiltration levels of different immune cells. IHC staining results further confirmed that the expression of CD44 in tumor cells was positively associated with the number of CD68⁺ macrophages and CD163⁺ macrophages (P < 0.05). Our results suggest that CD44 is a positive regulator of PD-L1 in BLCA and may be a key regulator of tumor macrophages infiltration and may be involved in M2 macrophage polarization. Our study provided new insights into the prognosis and immunotherapy of BLCA patients through macrophage infiltration and immune checkpoints.

International Opinions on Grading of Urothelial Carcinoma: A Survey Among European Association of Urology and International Society of Urological Pathology Members

Background

Grade of non-muscle-invasive bladder cancer (NMIBC) is an important prognostic factor for progression. Currently, two World Health Organization (WHO) classification systems (WHO1973, categories: grade 1-3, and WHO2004 categories: papillary urothelial neoplasm of low malignant potential [PUNLMP], low-grade [LG], high-grade [HG] carcinoma) are used.

Objective

To ask the European Association of Urology (EAU) and International Society of Urological Pathology (ISUP) members regarding their current practice and preferences of grading systems.

Design setting and participants

A web-based, anonymous questionnaire with ten questions on grading of NMIBC was created. The members of EAU and ISUP were invited to complete an online survey by the end of 2021. Thirteen experts had previously answered the same questions.

Outcome measurements and statistical analysis

The submitted answers from 214 ISUP members, 191 EAU members, and 13 experts were analyzed.

Results and limitations

Currently, 53% use only the WHO2004 system and 40% use both systems. According to most respondents, PUNLMP is a rare diagnosis with management similar to Ta-LG carcinoma. The majority (72%) would consider reverting back to WHO1973 if grading criteria were more detailed. Separate reporting of WHO1973-G3 within WHO2004-HG would influence clinical decisions for Ta and/or T1 tumors according the majority (55%). Most respondents preferred a two-tier (41%) or a three-tier (41%) grading system. The current WHO2004 grading system is supported by a minority (20%), whereas nearly half (48%) supported a hybrid three- or four-tier grading system composed of both WHO1973 and WHO2004. The survey results of the experts were comparable with ISUP and EAU respondents.

Conclusions

Both the WHO1973 and the WHO2004 grading system are still widely used. Even though opinions on the future of bladder cancer grading were strongly divided, there was limited support for WHO1973 and WHO2004 in their current formats, while the hybrid (three-tier) grading system with LG, HG-G2, and HG-G3 as categories could be considered the most promising alternative.

Patient summary

Grading of non-muscle-invasive bladder cancer (NMIBC) is a matter of ongoing debate and lacks international consensus. We surveyed urologists and pathologists of European Association of Urology and International Society of Urological Pathology on their preferences regarding NMIBC grading to generate a multidisciplinary dialogue. Both the "old" World Health Organization (WHO) 1973 and the "new" WHO2004 grading schemes are still used widely. However, continuation of both the WHO1973 and the WHO2004 system showed limited support, while a hybrid grading system composed of both the WHO1973 and the WHO2004 classification system may be considered a promising alternative.

Exploitation of tumor antigens and construction of immune subtype classifier for mRNA vaccine development in bladder cancer

Background

Bladder cancer (BLCA) is one of the most prevalent urinary system malignancies, with high mortality and recurrence. The present study aimed to identify potential tumor antigens for mRNA vaccines in BLCA and patient subtypes suitable for different immunotherapy.

Methods

Gene expression profiles, mutation data, methylation data, and corresponding clinical information were obtained from the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and ArrayExpress databases. Immunohistochemical staining of microarrays was performed to assess protein expression levels of IGF2BP2 and MMP9. Differential gene analysis, survival analysis, correlation analysis, consensus clustering analysis, and immune cell infiltration analysis were conducted using R software. Finally, the R package "immcluster" was used based on Combat and eXtreme Gradient Boosting algorithms to predict immune clusters of BLCA samples.

Results

Two mutated, amplified, and over-expressed tumor antigens, IGF2BP2 and MMP9, were found to be associated with clinical outcomes and the abundance of antigen-presenting cells (APCs). Subsequently, three immune subtypes (BIS1, BIS2, and BIS3) were defined in the BLCA cohort. BIS3 subtype exhibited an "active" immune phenotype, while BIS1 and BIS2 subtypes have a "suppressive" immune phenotype. Patients in BIS1 and BIS2 had a poor prognosis compared to BIS3. BIS3 had a higher score in checkpoints or immunomodulators (CP) and immunophenoscore (IPS), while BIS1 and BIS2 scored higher in major histocompatibility complex-related molecules (MHC molecules). Meanwhile, BIS2 and BIS3 had a significantly higher tumor mutational burden (TMB) compared to patients with BIS1. Finally, the "immcluster" package was applied to the dataset, which has been shown to accurately predict the immune subtypes of BLCA samples in many cohorts.

Conclusions

IGF2BP2 and MMP9 were potential antigens for developing mRNA vaccines against BLCA. The results in the present study suggested that immunotherapy targeting these two antigens would be suitable for patients falling under the BIS2 subtype. R package "immcluster" could assist in screening suitable BLCA patients for antitumor therapy.

Advances in Diagnosis and Therapy for Bladder Cancer

Simple Summary

The clinical management of bladder cancer has been developing in the past decade, including diagnostic tools and treatment options. Both monotherapy and combination therapy have been undoubtedly upgraded. Multiple diagnostic techniques and therapeutic strategies have been developed to meet the urgent clinical needs, resulting in the emergence of various explorations for cancer diagnosis and therapy. In this review, we mainly focus on the advances in the diagnosis and treatment of bladder cancer.

Abstract

Bladder cancer (BCa) is one of the most common and expensive urinary system malignancies for its high recurrence and progression rate. In recent years, immense amounts of studies have been carried out to bring a more comprehensive cognition and numerous promising clinic approaches for BCa therapy. The development of innovative enhanced cystoscopy techniques (optical techniques, imaging systems) and tumor biomarkers-based non-invasive urine screening (DNA methylation-based urine test) would dramatically improve the accuracy of tumor detection, reducing the risk of recurrence and progression of BCa. Moreover, intravesical instillation and systemic therapeutic strategies (cocktail therapy, immunotherapy, vaccine therapy, targeted therapy) also provide plentiful measures to break the predicament of BCa. Several exploratory clinical studies, including novel surgical approaches, pharmaceutical compositions, and bladder preservation techniques, emerged continually, which are supposed to be promising candidates for BCa clinical treatment. Here, recent advances and prospects of diagnosis, intravesical or systemic treatment, and novel drug delivery systems for BCa therapy are reviewed in this paper.