Tumor budding, a novel prognostic indicator for predicting stage progression in T1 bladder cancers

Prognostic value of isolated tumor cells and micrometastasis of lymph nodes in invasive urinary bladder cancer

INTRODUCTION

The prognostic significance of nodal micrometastasis and isolated tumor cells (ITC) in urinary bladder cancer (UBC) is unknown. We aimed to evaluate the prevalence, clinical impact, and clinicopathological characteristics of nodal micrometastasis and ITC in UBC.

MATERIALS AND METHODS

A total of 124 patients with UBC undergoing surgery were investigated. Detection of micrometastasis and ITC was performed using pancytokeratin immunohistochemistry (IHC). Histopathologic and clinical findings were correlated with patients' outcome.

RESULT

IHC detected nodal micrometastasis and ITC (pNmi group) in 12.9% (13/101) of originally node-negative patients and in 26.1% (6/23) of originally node-positive patients (pN+ group). The remaining 88 were truly node-negative patients (pN0 group). After IHC, all 13 patients in the pNmi group were upstaged from pN0 to pN1-2 and one patient in the pN+ group was changed from pN1 to pN2. Nodal micrometastasis and ITC were significantly associated with mixed urothelial carcinoma (UC) (p = 0.002), UC with discohesive pattern (p = 0.006), glandular differentiation (p = 0.043), lymphovascular invasion (p = 0.009), and budding-like tumor cell clusters (p = 0.002). The pNmi group had significantly worse cancer-specific survival than the pN0 group in univariate (p = 0.004) and multivariate (p = 0.040) analysis.

CONCLUSION

IHC frequently identified nodal micrometastasis and ITC in originally node-negative UBC patients on routine pathological examination. Nodal micrometastasis and ITC were independently associated with cancer-related mortality in UBC. IHC might be selectively used to detect micrometastasis and ITC in UBC having specific pathological features.

Digital and Computational Pathology Applications in Bladder Cancer: Novel Tools Addressing Clinically Pressing Needs

Bladder cancer (BC) remains a major disease burden in terms of incidence, morbidity, mortality, and economic cost. Deciphering the intrinsic molecular subtypes and identification of key drivers of BC has yielded successful novel therapeutic strategies. Advances in computational and digital pathology are reshaping the field of anatomical pathology. This review offers an update on the most relevant computational algorithms in digital pathology that have been proposed to enhance BC management. These tools promise to enhance diagnostics, staging, and grading accuracy and streamline efficiency while advancing practice consistency. Computational applications that enable intrinsic molecular classification, predict response to neoadjuvant therapy, and identify targets of therapy are also reviewed.

Is Immunohistochemical Galectin-3 Expression Associated with the Epithelial-Mesenchymal Transition in High- and Low-Grade Invasive Urothelial Carcinomas of the Bladder?

Background/Objectives: Bladder cancer, predominantly urothelial carcinoma, is an important malignancy of the urinary system. Despite the same histologic grade and stage, some patients seem to have a worse prognosis. In this context, the epithelial-mesenchymal transition (EMT), characterized by the loss of E-cadherin and gain of vimentin expression, is an important process in tumor progression. Galectin-3, a lactose-binding protein involved in various cellular processes, has been associated with increased tumor cell migration, invasion, and treatment resistance. Methods: In this study, 223 bladder cancer cases were examined, and E-cadherin, vimentin, and galectin-3 expression was evaluated by immunohistochemical staining in tumor budding areas and invasive components. These markers were also correlated with clinicopathological parameters, including tumor grade and stage. Results: The results indicated a significant decrease in E-cadherin expression and an increase in vimentin staining in higher-grade and higher-stage tumors, supporting EMT involvement. Galectin-3 expression was notably higher in T1 high-grade tumors but decreased in T2 stage tumors. Despite this, no significant correlation was found between galectin-3 and E-cadherin or vimentin, suggesting a complex role of galectin-3 in EMT. Conclusions: High galectin-3 expression in T1 high-grade tumors highlights its potential role in early tumor progression and as a therapeutic target. However, the decrease in its expression in advanced stages underscores the need for further research to understand its multifaceted involvement in bladder cancer. These findings suggest that while galectin-3 may contribute to the EMT and early tumor progression, its exact role and potential as a therapeutic target require more detailed investigation.

A novel grading approach predicts worse outcomes in stage pT1 non-muscle-invasive bladder cancer

OBJECTIVE

To develop a prognostically relevant scoring system for stage pT1 non-muscle-invasive bladder cancer (NMIBC) incorporating tumour budding, growth pattern and invasion pattern because the World Health Organisation grading system shows limited prognostic value in such patients.

PATIENTS AND METHODS

The tissue specimens and clinical data of 113 patients with stage pT1 NMIBC who underwent transurethral resection of bladder tumour were retrospectively investigated. Tumour budding, and growth and invasion patterns were evaluated and categorised into two grade groups (GGs). GGs and other clinical and histopathological variables were investigated regarding recurrence-free survival (RFS), progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS) using univariable and multivariable Cox regression analyses.

RESULTS

The integration of two tumour budding groups, two growth patterns, and two invasion patterns yielded an unfavourable GG (n = 28; 24.7%) that had a high impact on oncological outcomes. The unfavourable GG was identified as an independent RFS and OS predictor (P = 0.004 and P = 0.046, respectively) and linked to worse PFS (P = 0.001) and CSS (P = 0.001), irrespective of the European Association of Urology risk group. The unfavourable GG was associated with higher rates of BCG-unresponsive tumours (P = 0.006). Study limitations include the retrospective, single-centre design, diverse therapies and small cohort.

CONCLUSIONS

We present a morphology-based grading system for stage pT1 NMIBC that correlates with disease aggressiveness and oncological patient outcomes. It therefore identifies a highest risk group of stage pT1 NMIBC patients, who should be followed up more intensively or receive immediate radical cystectomy. The grading incorporates objective variables assessable on haematoxylin and eosin slides and immunohistochemistry, enabling an easy-to-use low-cost approach that is applicable in daily routine. Further studies are needed to validate and confirm these results.

Predicting prognosis in intrahepatic cholangiocarcinoma by the histopathological features

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a highly heterogeneous liver tumor. The associations between histopathological feature and prognosis of ICC are limited. The present study aimed to investigate the prognostic significance of glandular structure and tumor budding in ICC.

METHODS

Patients received radical hepatectomy for ICC were included. Glandular structure and tumor budding were detected by Hematoxylin-eosin staining. The Kaplan-Meier method and the Cox proportional hazards regression model were used to calculate the survival and hazard ratio. Based on the results of multivariate analysis, nomograms of OS and DFS were constructed. C-index and Akaike information criterion (AIC) were used to assess accuracy of models.

RESULTS

A total of 323 ICC patients who underwent surgery were included in our study. Glandular structure was associated with worse overall survival (OS) [hazard ratio (HR): 2.033, 95% confidence interval (CI): 1.047 to 3.945] and disease-free survival (DFS) [HR: 1.854, 95% CI: 1.082 to 3.176]. High tumor budding was associated with worse DFS [HR: 1.636, 95%CI: 1.060 to 2.525]. Multivariate analysis suggested that glandular structure, tumor number, lymph node metastasis, and CA19-9 were independent risk factors for OS. Independent predictor factors for DFS were tumor budding, glandular structure, tumor number, and lymph node metastasis. The c-index (0.641 and 0.642) and AIC (957.69 and 1188.52) showed that nomograms of OS and DFS have good accuracy.

CONCLUSION

High tumor budding and glandular structure are two important histopathological features that serve as prognostic factors for ICC patients undergoing hepatectomy.

Proposal for a Novel Histological Scoring System as a Potential Grading Approach for Muscle-invasive Urothelial Bladder Cancer Correlating with Disease Aggressiveness and Patient Outcomes

BACKGROUND

Grading of muscle-invasive bladder cancer (MIBC) according to the current World Health Organization (WHO) criteria is controversial due to its limited prognostic value. All MIBC cases except a tiny minority are of high grade.

OBJECTIVE

To develop a prognostic histological scoring system for MIBC integrating histomorphological phenotype, stromal tumor-infiltrating lymphocytes (sTILs), tumor budding, and growth and spreading patterns.

DESIGN, SETTING, AND PARTICIPANTS

Tissue specimens and clinical data of 484 patients receiving cystectomy and lymphadenectomy with curative intent with or without adjuvant chemotherapy. Histomorphological phenotypes, sTILs, tumor budding, and growth and spreading patterns were evaluated and categorized into four grade groups (GGs). GGs were correlated with molecular subtypes, immune infiltration, immune checkpoint expression, extracellular matrix (ECM) remodeling, and epithelial-mesenchymal transition (EMT) activity.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

GGs were associated with overall (OS), disease-specific (DSS), and progression-free (PFS) survival in univariable and multivariable analyses. Association with biological features was analyzed with descriptive statistics.

RESULTS AND LIMITATIONS

Integration of two histomorphological tumor groups, three sTILs groups, three tumor budding groups, and four growth/spread patterns yielded four novel GGs that had high significance in the univariable survival analysis (OS, DSS, and PFS). GGs were confirmed as independent prognostic predictors with the greatest effect in the multivariable Cox regression analysis. Correlation with molecular data showed a gradual transition from basal to luminal subtypes from GG1 to GG4; a gradual decrease in survival, immune infiltration, and immune checkpoint activity; and a gradual increase in ECM remodeling and EMT activity.

CONCLUSIONS

We propose a novel, prognostically relevant, and biologically based scoring system for MIBC in cystectomies applicable to routine pathological sections.

PATIENT SUMMARY

We developed a novel approach to assess the aggressiveness of advanced bladder cancer, which allows improved risk stratification compared with the method currently proposed by the World Health Organization.

Prognostic Value of Tumor Budding in Urothelial Carcinoma: A Meta-Analysis and Systematic Review

Recently, tumor budding (TB) has been suggested as a strong prognostic marker in urinary tract urothelial carcinoma (UC). The aim of this systematic review is to test the prognostic value of TB in UC by a meta-analysis of previously published studies. We systematically reviewed the literature related to TB by using the databases of Scopus, PubMed, and Web of Science. The search was limited to publications in the English language up to July 2022. There were 790 patients from 7 retrospective studies in which TB has been evaluated in UC. Two authors independently extracted the results from eligible studies. The meta-analysis of eligible studies revealed that TB is a significant prognosticator for progression-free survival in UC, with a hazard ratio (HR) of 3.51 (95% CI, 1.86-6.62; P < .001) in univariate analysis and a HR of 2.78 (95% CI, 1.57-4.93; P < .001) in multivariate analysis; a significant prognosticator for overall survival and cancer-specific survival in UC, with a HR of 3.07 (95% CI, 2.04-4.64; P < .001) and a HR of 2.18 (95% CI, 1.11-4.29; P = .02) respectively in univariate analysis. Our findings confirm that UC with a high TB count is at a high risk of progress. TB could be considered as an element in pathology reports and future oncologic staging systems.

Polyploid giant cancer cells and cancer progression

Polyploid giant cancer cells (PGCCs) are an important feature of cellular atypia, the detailed mechanisms of their formation and function remain unclear. PGCCs were previously thought to be derived from repeated mitosis/cytokinesis failure, with no intrinsic ability to proliferate and divide. However, recently, PGCCs have been confirmed to have cancer stem cell (CSC)-like characteristics, and generate progeny cells through asymmetric division, which express epithelial-mesenchymal transition-related markers to promote invasion and migration. The formation of PGCCs can be attributed to multiple stimulating factors, including hypoxia, chemotherapeutic reagents, and radiation, can induce the formation of PGCCs, by regulating the cell cycle and cell fusion-related protein expression. The properties of CSCs suggest that PGCCs can be induced to differentiate into non-tumor cells, and produce erythrocytes composed of embryonic hemoglobin, which have a high affinity for oxygen, and thereby allow PGCCs survival from the severe hypoxia. The number of PGCCs is associated with metastasis, chemoradiotherapy resistance, and recurrence of malignant tumors. Targeting relevant proteins or signaling pathways related with the formation and transdifferentiation of adipose tissue and cartilage in PGCCs may provide new strategies for solid tumor therapy.

Prognostic value of tumour budding in stomach cancers

OBJECTIVE

The present study aimed to investigate the importance and prognostic value of tumour budding (TB) in Gastric Carcinoma (GC).

METHODS

Pathologic grading of tumours was performed according to the criteria specified by the American Joint Committee on Cancer (AJCC). Histopathologic types, histopathologic grading and all histopathologic characteristics were determined using the Lauren and World Health Organization (WHO) classifications. Forty-three surgically treated GC cases were examined in terms of TB according to the International Tumor Budding Consensus Conference (ITBCC) and budding grading [budding degree (Bd)] was performed. They were recorded as Bd1 (1-4 buddings), Bd2 (5-9 buddings) or Bd3 (10 buddings or more). Bd score, clinicopathologic parameters and prognostic factors were analysed.

RESULTS

There were 13 (30.2%) Bd1, 11 (25.6%) Bd2 and 19 (44.2%) Bd3 cases. A statistically significant relationship was found between Bd scores and pT, N, and histologic grade (P < .01, P < .05). In the Bd1 group, stage pT2 was statistically significantly more frequent than pT3 (P = .001). In the poorly differentiated group, Bd3 was statistically significantly higher than Bd1, but Bd1 was statistically significantly higher than Bd2 in the well-differentiated group (P = .001). In the N0 group, Bd1 was significantly higher than Bd2 and Bd3, whereas Bd2 was higher than Bd1 and Bd3 in the N2 group. Bd3 was higher than Bd1 and Bd2 in the N3 group (P = .001).

CONCLUSION

In the present study, Bd was statistically significantly related to characteristics such as pathologic stage, lymph node involvement, and grade. The data obtained here suggest that Bd can be applied to GC and it might contribute to the standardisation of diagnosis and prognostic factors.

Single-Cell Proteomic Analysis Dissects the Complexity of Tumor Microenvironment in Muscle Invasive Bladder Cancer

Simple Summary

The tumor microenvironment (TME) is considered to play a key role in the development of many types of tumors. Muscle invasive bladder cancer (MIBC), which is well known for its heterogeneity, has a highly complex TME. Herein, we integrated mass cytometry and imaging mass cytometry to systematically investigate the complexity of the MIBC TME. Our investigation revealed tumor and immune cells with diverse phenotypes. We identified a specific cancer stem-like cell cluster (ALDH⁺PD-L1⁺ER-β⁻), which is associated with poor prognosis and highlighted the importance of the spatial distribution patterns of MIBC TME components. The present study comprehensively elucidated the complexity of the MIBC TME and provides potentially valuable information for future research.

Abstract

Muscle invasive bladder cancer (MIBC) is a malignancy with considerable heterogeneity. The MIBC tumor microenvironment (TME) is highly complex, comprising diverse phenotypes and spatial architectures. The complexity of the MIBC TME must be characterized to provide potential targets for precision therapy. Herein, an integrated combination of mass cytometry and imaging mass cytometry was used to analyze tumor cells, immune cells, and TME spatial characteristics of 44 MIBC patients. We detected tumor and immune cell clusters with abnormal phenotypes. In particular, we identified a previously overlooked cancer stem-like cell cluster (ALDH⁺PD-L1⁺ER-β⁻) that was strongly associated with poor prognosis. We elucidated the different spatial architectures of immune cells (excluded, infiltrated, and deserted) and tumor-associated collagens (curved, stretched, directionally distributed, and chaotic) in the MIBC TME. The present study is the first to provide in-depth insight into the complexity of the MIBC TME at the single-cell level. Our results will improve the general understanding of the heterogeneous characteristics of MIBC, potentially facilitating patient stratification and personalized therapy.

A novel self-learning framework for bladder cancer grading using histopathological images

In recent times, bladder cancer has increased significantly in terms of incidence and mortality. Currently, two subtypes are known based on tumour growth: non-muscle invasive (NMIBC) and muscle-invasive bladder cancer (MIBC). In this work, we focus on the MIBC subtype because it has the worst prognosis and can spread to adjacent organs. We present a self-learning framework to grade bladder cancer from histological images stained by immunohistochemical techniques. Specifically, we propose a novel Deep Convolutional Embedded Attention Clustering (DCEAC) which allows for the classification of histological patches into different levels of disease severity, according to established patterns in the literature. The proposed DCEAC model follows a fully unsupervised two-step learning methodology to discern between non-tumour, mild and infiltrative patterns from high-resolution 512 × 512 pixel samples. Our system outperforms previous clustering-based methods by including a convolutional attention module, which enables the refinement of the features of the latent space prior to the classification stage. The proposed network surpasses state-of-the-art approaches by 2-3% across different metrics, reaching a final average accuracy of 0.9034 in a multi-class scenario. Furthermore, the reported class activation maps evidence that our model is able to learn by itself the same patterns that clinicians consider relevant, without requiring previous annotation steps. This represents a breakthrough in MIBC grading that bridges the gap with respect to training the model on labelled data.

Recent Advances in the Management of Patients with Non-Muscle-Invasive Bladder Cancer Using a Multidisciplinary Approach: Practical Recommendations from the Spanish Oncology Genitourinary (SOGUG) Working Group

Simple Summary

This report presents clinically relevant advances in the management of non-muscle-invasive bladder cancer, which have been the focus of discussion of expert members of the Spanish Oncology Genitourinary (SOGUG) Multidisciplinary Working Group in the framework of the Genitourinary Alliance project (12GU), designed as a space for the integration of novel information in the care of bladder cancer patients. The present study is focused on different aspects regarding the evaluation of hematuria, assessment of second (or repeated) transurethral resection of bladder cancer, histopathological diagnosis and problems with tumor grading, importance of histological variants, shortage of drug supply, and the current role and influence of immunotherapy and biological markers on the oncological outcome of patients. All proposals and recommendations have a multidisciplinary practical approach and are intended to help clinicians in shared decision making for patients with non-muscle-invasive urothelial cancer.

Abstract

On the basis of the discussion of the current state of research on relevant topics of non-muscle-invasive bladder cancer (NMIBC) among a group of experts of the Spanish Oncology Genitourinary (SOGUG) Working Group, recommendations were proposed to overcome the challenges posed by the management of NMIBC in clinical practice. A unified definition of the term ‘microhematuria’ and the profile of the patient at risk are needed. Establishing a ‘hematuria clinic’ would contribute to a centralized and more efficient evaluation of patients with this clinical sign. Second or repeated transurethral resection (re-TUR) needs to be defined, including the time window after the first procedure within which re-TUR should be performed. Complete tumor resection is mandatory when feasible, with specification of the presence or absence of muscle. Budding should be used as a classification system, and stratification of T1 tumors especially in extensive and deep tumors, is advisable. The percentage of the high-grade component should always be reported, and, in multiple tumors, grades should be reported separately. Luminal and basal subtypes can be identified because of possibly different clinical outcomes. Molecular subtypes and immunotherapy are incorporated in the management of muscle-invasive bladder cancer but data on NMIBC are still preliminary.

Tumor budding correlates with tumor invasiveness and predicts worse survival in pT1 non-muscle-invasive bladder cancer

Tumor budding is defined as a single cell or a cluster of up to 5 tumor cells at the invasion front. Due to the difficulty of identifying patients at high risk for pT1 non-muscle-invasive bladder cancer (NMIBC) and the difficulties in T1 substaging, tumor budding was evaluated as a potential alternative and prognostic parameter in these patients. Tumor budding as well as growth pattern, invasion pattern and lamina propria infiltration were retrospectively evaluated in transurethral resection of the bladder (TURB) specimens from 92 patients with stage pT1 NMIBC. The presence of tumor budding correlated with multifocal tumors (p = 0.003), discontinuous invasion pattern (p = 0.039), discohesive growth pattern (p < 0.001) and extensive lamina propria invasion (p < 0.001). In Kaplan-Meier analysis, tumor budding was associated with significantly worse RFS (p = 0.005), PFS (p = 0.017) and CSS (p = 0.002). In patients who received BCG instillation therapy (n = 65), the absence of tumor budding was associated with improved RFS (p = 0.012), PFS (p = 0.011) and CSS (p = 0.022), with none of the patients suffering from progression or dying from the disease. Tumor budding is associated with a more aggressive and invasive stage of pT1 NMIBC and a worse outcome. This easy-to-assess parameter could help stratify patients into BCG therapy or early cystectomy treatment groups.

Prognostic significance of tumor budding in muscle invasive urothelial carcinomas of the urinary bladder

OBJECTIVE

The aim of the present study was to analyze the prognostic significance of tumor budding in muscle-invasive urothelial carcinomas of the urinary bladder, and also to determine an optimal threshold value in evaluation.

PATIENTS AND METHODS

The study included 108 patients diagnosed with muscleinvasive conventional urothelial carcinoma between 2010 and 2020. Tumor budding was evaluated on H&E-stained slides. The critical tumor budding number was determined with the "receiver operating characteristics (ROC)" curve. Cases with a tumor budding number of ≤6 were categorized as low, and cases with >6 as high tumor budding.

RESULTS

The univariate Cox proportional hazards regression model for recurrence-free survival showed that lymphovascular invasion (P = 0.001), tumor budding (P = 0.012), pT stage (T4 vs. T2) (P = 0.005), and lymph node metastasis (P = 0.009) were significantly associated with recurrence-free survival. The multivariate Cox proportional hazards regression model utilizing backward stepwise (wald) method revealed that only LVI (P = 0.001) was independent risk factor for recurrence-free survival. The univariate Cox analysis showed that lymphovascular invasion (P = 0.001), tumor budding (P = 0.004), pT stage (T4 vs. T2) (P = 0.003), and lymph node metastasis (P = 0.001) were significantly associated with overall survival. The multivariate Cox analysis (backward stepwise (wald) method) revealed that tumor focality (P = 0.018), pT stage (T4 vs. T2) (P = 0.015), and lymphovascular invasion (P = 0.002) were independent factors for overall survival.

CONCLUSIONS

Our findings suggested that the evaluation of tumor budding may be a useful parameter for predicting outcome in patients with muscle-invasive bladder cancer.

Joint Tumor Bud-MMP/TIMP Count at the Invasive Front Improves the Prognostic Evaluation of Invasive Breast Carcinoma

BACKGROUND

Tumor budding is a histological phenomenon consisting of the formation of small clusters of one to five undifferentiated malignant cells detached from the main tumor mass which are observed in the tumor stroma. In the present study, we investigated the prognostic significance of tumor budding in breast cancer and its relationship with the expressions of matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs).

METHODS

The number of buds was counted in whole-tissue sections from 153 patients with invasive ductal carcinomas who underwent a long follow-up period. In addition, an immunohistochemical study of MMP-9, -11, and -14 TIMP-1 and -2 expression by cell types at the invasive tumor front was carried out.

RESULTS

There was a wide variability in the number of buds among tumors, ranging from 0 to 28 (median = 5). Tumor budding count ≥ 4 was the optimal cut-off to predict both relapse-free and overall survival. High-grade tumor budding was associated with MMP/TIMP expression by cancer-associated fibroblasts. In addition, we found that the combination of tumor budding grade with MMP/TIMP expression by stromal cells, and especially with MMP-11 expression by mononuclear inflammatory cells, significantly improved the prognostic evaluation.

CONCLUSION

High-grade tumor budding is associated with a more aggressive tumor phenotype, which, combined with MMP/TIMP expression by stromal cells at the invasive front of the tumor, identifies patients with poor prognosis.

Tumor budding in upper urinary tract urothelial carcinoma: a putative prognostic factor for extraurothelial recurrence and overall survival

Tumor budding, defined as a single cancer cell or clusters of fewer than five cancer cells observed at the tumor invasion front, has been reported to be associated with poor prognosis in various types of cancers. However, limited information regarding the pathological and prognostic significance of tumor budding in upper urinary tract urothelial carcinoma (UUTUC) is available. We investigated 135 consecutive patients with newly diagnosed invasive UUTUCs (73 with renal pelvic cancers and 62 with ureteral cancers) treated with nephroureterectomy or partial ureterectomy between 1999 and 2018 in our hospital. Under a × 200 magnification, tumors with 10 or more budding foci were defined as "high tumor budding". The median follow-up period was 53.6 months. Among the 135 patients, 41 (30%; 16 with renal pelvic cancers and 25 with ureteral cancers) showed high tumor budding. High tumor budding was related to adjuvant chemotherapy status, higher pathological T stage, lymphovascular invasion, lymph node metastasis, tumor location, concomitant variant histology, and non-papillary gross finding. The multivariate Cox analysis revealed that LVI and high tumor budding were independent predictors for extraurothelial recurrence (P = 0.039 and 0.014, hazard ratio = 2.50 and 2.88, respectively), and high tumor budding was an independent predictor for overall survival (P = 0.024, hazard ratio = 2.33). Tumor budding can be easily introduced in clinical practice with no need for immunohistochemical analysis, may be an important clinicopathological factor of UUTUC, and is suggested to be useful as a novel predictive prognostic factor of patients with invasive UUTUC.

Bladder cancer in the time of machine learning: Intelligent tools for diagnosis and management

Machine learning (ML) is the subfield of artificial intelligence (AI), born from the marriage between statistics and computer science, with the unique purpose of building prediction algorithms able to improve their performances by automatically learning from massive data sets. The availability of ever-growing computational power and highly evolved pattern recognition software has led to the spread of ML-based systems able to perform complex tasks in bioinformatics, medical imaging, and diagnostics. These intelligent tools could be the answer to the unmet need for non-invasive and patient-tailored instruments for the diagnosis and management of bladder cancer (BC), which are still based on old technologies and unchanged nomograms. We reviewed the most significant evidence on ML in the diagnosis, prognosis, and management of bladder cancer, to find out if these intelligent technologies are ready to be introduced into the daily clinical practice of the urologist.

Histologically confirmed distant metastatic urothelial carcinoma from the urinary bladder: a retrospective review of one institution's 20-year experience

Background

Urothelial carcinoma (UC) accounts for roughly 90% of bladder cancer, and has a high propensity for diverse differentiation. Recently, certain histologic variants of UC have been recognized to be associated with unfavorable clinical outcomes. Several UC studies have also suggested that tumor budding is a poor prognostic marker. Distant metastasis of UC after radical cystectomy is not uncommon. However, these metastatic lesions are not routinely confirmed with histology.

Methods

We investigated the histopathologic features of 13 cases of UC with biopsy-proven distant metastases, with a special emphasis on histologic variants and tumor budding.

Results

Lymph nodes (6/13, 46%) were the most common metastatic sites, followed by the lung (4/13, 31%), liver (4/13, 31%), and the adrenal gland (2/13, 15%). The histologic variants including squamous (n = 1), micropapillary (n = 4), and plasmacytoid (n = 1) variants in five cases of UC. Most histologic variants (4/5, 80%) of primary UCs appeared in the metastatic lesions. In contrast, high-grade tumor budding was detected in six cases (46%), including one case of non-muscle invasive UC. Our study demonstrates that histologic variants are not uncommonly detected in distant metastatic UCs. Most histologic variants seen in primary UCs persist in the distant metastatic lesions. In addition, high-grade tumor budding, which occurs frequently in primary tumors, may contribute to the development of distant metastasis.

Conclusions

Therefore, assessing the presence or absence of histologic variants and tumor budding in UCs of the urinary bladder, even in non-muscle invasive UCs, may be useful to predict distant metastasis.

Stage T1 bladder cancer: diagnostic criteria and pitfalls

Accurate pathological staging is crucial for patient management. Patients with T1 bladder cancer are at risk of recurrence, progression, and death of cancer. Recognition of early invasion (stage T1 disease) in urothelial carcinoma remains one of the most challenging areas in urological surgical pathology practice. A logical roadmap to T1 diagnosis would include careful evaluation of histological grade, stromal epithelial interface, characteristics of the invading epithelium, and the stroma associated responses. Tangential sectioning, crush and cautery artifacts, and associated inflammatory infiltrate are commonly encountered problems and the source of pitfalls. In this review, we outline diagnostic criteria, common pitfalls, and different histological patterns of invasion into the lamina propria. Current recommendations on reporting of biopsy and transurethral resection specimens, molecular biomarkers, clinical implications of T1 cancer diagnosis and recent developments on the T1 substaging are also discussed. Most T1 bladder cancer patients will benefit from conservative management after restaging transurethral resection of bladder and bacillus Calmette-Guérin maintenance. Patients with high risk features, such as concurrent urothelial carcinoma in situ, increased depth of invasion, lymphovascular invasion, and variant histology among others, should be considered for early cystectomy.

The budding and depth of invasion model in oral cancer: A systematic review and meta-analysis

BACKGROUND

Tumour budding (B) and depth of invasion (D) have both been reported as promising prognostic markers in oral squamous cell carcinoma (OSCC). This meta-analysis assessed the prognostic value of the tumour budding and depth of invasion combination (BD model) in OSCC.

METHODS

Databases including Ovid MEDLINE, PubMed, Scopus and Web of Science were searched for articles that studied the BD model as a prognosticator in OSCC. PICO search strategy was "In OSCC patients, does BD model have a prognostic power?" We used the reporting recommendations for tumour marker prognostic studies (REMARK) criteria to evaluate the quality of studies eligible for systematic review and meta-analysis.

RESULTS

Nine studies were relevant as they analysed the BD model for prognostication of OSCC. These studies used either haematoxylin and eosin (HE) or pan-cytokeratin (PCK)-stained resected sections of OSCC. Our meta-analysis showed a significant association of BD model with OSCC disease-free survival (hazard ratio = 2.02; 95% confidence interval = 1.44-2.85).

CONCLUSIONS

The BD model is a simple and reliable prognostic indicator for OSCC. Evaluation of the BD model from HE- or PCK-stained sections could facilitate individualized treatment planning for OSCC patients.

Predictive significance of tumor budding in postoperative liver metastasis of pancreatic neuroendocrine tumors

BACKGROUND

Although pancreatic neuroendocrine tumors (PNETs) are considered indolent tumors, nearly half of cases metastasize to the liver, which can be lethal. However, effective indicators to predict aggressive behavior have not been well-established.

METHODS

In the current study, we explored the prognostic significance of tumor budding in Grade 1-2 PNETs. Hematoxylin-eosin and immunohistochemically stained slides of surgically removed Grade 1-2 PNETs were evaluated.

RESULTS

Tumor budding, a histomorphological parameter that corresponds to single cells or small cell clusters (<5 cells), was classified as low (0-10 buds) and high (>10 buds) grade. We observed that tumor budding was correlated with aggressive histopathological parameters, such as T stage, lymph node status, metastasis, and vascular invasion (p < .05). Univariate and multivariate analyses showed that high-grade budding was an independent predictive factor for postoperative liver metastasis (p = .012). Moreover, Grade 1-2 PNETs with high-grade budding was associated with worse overall survival and disease-free survival (p = .0015 and p = .0041, respectively).

CONCLUSIONS

We conclude that tumor budding may serve as a valuable parameter in the risk stratification of postoperative liver metastasis and that incorporating tumor budding into histopathological reports may aid in appropriate clinical management.

Prognostic significance of peritumoural and intratumoural budding in intestinal-type gastric adenocarcinoma

BACKGROUND AND STUDY AIMS

Tumour budding (TB) at the invasive front, termed peritumoural budding (PTB), is an established prognostic factor for many solid tumours. However, intratumoural budding (ITB) in gastric adenocarcinoma (GAC), which is frequently observed at the tumour centre, particularly in tumour biopsy tissues, remains poorly understood. Hence, we aimed to determine the correlation of ITB with PTB and their connection with clinicopathological characteristics as well as their prognostic value in GAC.

PATIENTS AND METHODS

We investigated a total of 153 cases of GAC wherein tissues were primarily resected and their related clinicopathological data. A continuous series of paraffin-embedded tissues was stained by haematoxylin-eosin staining, and budding cells were identified by immunohistochemical staining. PTB and ITB were counted in five fields with the highest density of tumour buds. The selected area was examined under 40 high-power field. Cases were divided into low-grade TB and high-grade TB groups according to the median bud count.

RESULTS

Among the 153 patients with GAC, 51 underwent simultaneous observation of ITB and PTB, which were found to have a significant positive correlation. A higher grade of ITB in tumours was associated with positive lymph node metastasis and could predict a worse prognosis. Additionally, patients with simultaneous PTB and ITB had a shorter overall survival than those with PTB alone, suggesting a worse prognosis.

CONCLUSION

PTB and ITB were found to be adverse prognostic factors and high-risk indicators of intestinal-type GAC, and ITB plays an important role in evaluating GAC prognosis in gastroscopic biopsy tissues. Additionally, TB might become a useful index for predicting GAC prognosis in the future.

A classification based on tumor budding and immune score for patients with hepatocellular carcinoma

Background: The role of immune profiling and tumor budding in hepatocellular carcinoma (HCC) remains largely unknown. This study evaluated the association between tumor budding and lymphocytic infiltration in HCC. Meanwhile, HCC patients were stratified based on tumor budding grade and immune score.

Patients and methods: A total of 423 HCC patients were divided into training (n = 212) and validation (n = 211) cohort. Tumor slides from resected HCC samples were used for tumor budding assessment. A prognosis-relevant immune score was developed based on five types of immune cells out of eleven immune markers. A classification based on tumor budding grade and immune type was established (IS-TB type). To explore the association of IS-TB type and molecular alterations of HCC, 100 HCC samples and adjacent non-tumor tissues from 100 patients were investigated by whole-exome sequencing.

Results: Tumor budding was an independent adverse prognostic factor for OS and DFS in both of the training and validation cohorts (all P values <.05). The rate of high-grade tumor budding was significantly higher in HCC with immature stroma (P < .001), strong α-SMA expression (P = .005), non-steatotic tumors and non-fibrolamellar-HCC (P < .001). Additionally, tumor budding was related to both anti- and pro-tumor immune responses. Patients were classified into immune type A and immune type B according to the immune score. Based on tumor budding grade and immunotype, patients were classified into four subgroups: IS_A-TB_high (type I), IS_B-TB_high (type II), IS_A-TB_low (type III) and IS_B-TB_low (type IV). Patients with type III tumor had the best OS and DFS, whereas OS and DFS were the worst for cases with type II tumor. TP53 mutation was more frequent in IS-TB type I (IS_ATB_high) patients, while IS-TB type IV (IS_BTB_low) harbored high number of CTNNB1 mutation.

Conclusion: Tumor-immune cell interactions in HCC is heterogeneous. HCC classification based on tumor budding and immune score correlates with patient survival and molecular alterations. The defined subtypes may have significance for utilizing individualized treatment in patients with HCC.

Automated tumour budding quantification by machine learning augments TNM staging in muscle-invasive bladder cancer prognosis

Tumour budding has been described as an independent prognostic feature in several tumour types. We report for the first time the relationship between tumour budding and survival evaluated in patients with muscle invasive bladder cancer. A machine learning-based methodology was applied to accurately quantify tumour buds across immunofluorescence labelled whole slide images from 100 muscle invasive bladder cancer patients. Furthermore, tumour budding was found to be correlated to TNM (p = 0.00089) and pT (p = 0.0078) staging. A novel classification and regression tree model was constructed to stratify all stage II, III, and IV patients into three new staging criteria based on disease specific survival. For the stratification of non-metastatic patients into high or low risk of disease specific death, our decision tree model reported that tumour budding was the most significant feature (HR = 2.59, p = 0.0091), and no clinical feature was utilised to categorise these patients. Our findings demonstrate that tumour budding, quantified using automated image analysis provides prognostic value for muscle invasive bladder cancer patients and a better model fit than TNM staging.

Does evaluation of tumour budding in diagnostic biopsies have a clinical relevance? A systematic review

Tumour budding has emerged as a promising prognostic marker in many cancers. We systematically reviewed all studies that evaluated tumour budding in diagnostic biopsies. We conducted a systematic review of PubMed, MEDLINE, Scopus, Web of Science and Cochrane library for all articles that have assessed tumour budding in diagnostic (i.e. pretreatment or pre-operative) biopsies of any tumour type. Two independent researchers screened the retrieved studies, removed duplicates, excluded irrelevant studies and extracted data from the eligible studies. A total of 13 reports comprising 11 cohorts were found to have studied tumour budding in diagnostic biopsies. All these reports showed that evaluation of tumour budding in diagnostic biopsies was easily applicable. A strong association was observed between tumour budding score in diagnostic biopsies and corresponding surgical samples. Evaluation of tumour budding in diagnostic biopsies had a significant prognostic value for lymph node metastasis and patient survival. In all studies, tumour budding was a valuable marker of tumour aggressiveness and can be evaluated in technically satisfactory diagnostic biopsies. Thus, the assessment of tumour budding seems to identify the behaviour of cancer, and therefore to facilitate treatment planning.

National Cancer Database Comparison of Radical Cystectomy vs Chemoradiotherapy for Muscle-Invasive Bladder Cancer: Implications of Using Clinical vs Pathologic Staging

PURPOSE

To test the hypothesis that bladder preservation therapy consisting of definitive chemoradiotherapy (chemoRT) results in similar overall survival rates to radical cystectomy/chemotherapy when balancing baseline patient characteristics and initial (preoperative) clinical stage.

MATERIALS/METHODS

A total of 7,322 patients with stage II-IV, M0 bladder cancer who were treated with cystectomy/chemo (N = 5,664) or definitive chemoRT (N = 1,658) were identified from the National Cancer Database. Baseline patient characteristics were compared using Pearson's chi-square, Fisher's exact test, and Wilcoxon's rank sum tests. Cox regressions were used to investigate for variables significantly correlated with overall survival (OS). OS was compared between cystectomy/chemo vs chemoRT before and after propensity score matched pair analyses using Kaplan-Meier curves and log-rank tests.

RESULTS

Patients who underwent cystectomy/chemo were significantly younger than ones treated with definitive chemoRT (mean age 63.7 vs 75.2; P < 0.001). Age, race, Charlson/Deyo Comorbidity Score (CDCS), clinical stage, insurance status, and type of facility significantly correlated with OS (P < 0.05 for all covariates). Patients treated with cystectomy/chemo were younger, healthier with better CDCS, and more likely treated at academic facilities. Before matched pair analyses, OS was significantly better when treated with cystectomy/chemo (3 year 56.4%; 5 year 45.9%) compared to chemoRT (3 year 47.3%; 5 year 33.2%) (P < 0.001); 28.6% of patients undergoing cystectomy were upstaged at the time of surgery. After matched pair analyses matching age, race, sex, CDCS, clinical (presurgical) stage, insurance, and facility type (N = 1,750), OS was no longer significantly different between cystectomy/chemo (3 year 52.1% and 5 year 41.0%) vs chemoRT (3 year 53.3% and 5 year 40.1%) (P = 0.5).

CONCLUSIONS

Patients treated with cystectomy/chemo were significantly younger and healthier compared to those treated with chemoRT. Once these factors were accounted for in propensity score matched pair analyses using clinical stage, overall survival was not significantly different between cystectomy/chemo and an organ-sparing approach with definitive chemoRT.

Prognostic significance of tumor budding in muscle invasive urothelial carcinomas of the bladder

OBJECTIVE

The aim of this study was to evaluate the prognostic significance of tumor budding in muscle invasive urothelial carcinoma of bladder (MIBC).

MATERIAL AND METHODS

A total of 60 patients who underwent radical cystectomy and cystoprostatectomy for MIBC were included in the study. The correlations between tumor budding, and tumor necrosis, lymphovascular invasion (LVI), perineural invasion (PNI) and histopathological data with distant metastasis were evaluated. The correlation between progression free (PFS) and overall survival (OS) rates and the presence, and grade of tumor budding was investigated.

RESULTS

A statistically significant correlation was not seen between tumor budding, necrosis, LVI, and PNI. There was a strong correlation between distant organ metastasis, and presence of tumor necrosis. There was no statistically significant correlation between PFS, OS and tumor budding. A statistically significant relationship was observed between OS and tumor stage, lymph node metastasis, and distant organ metastasis.

CONCLUSION

In our study, statistically significant effect of tumor budding on survival rates in MIBCs was not observed. Also, no significant correlation was observed between tumor budding and tumor necrosis, LVI, and PNI.

Predicting the tumorigenic phenotype of human bladder cancer cells by combining with fetal rat mesenchyme

BACKGROUND

In nonmuscle invasive bladder cancer patients, prediction of pTa and pT1 bladder cancer recurrence and progression must be established. Micropapillary structures have been defined as small clusters of invasive cancer cells having features of the epithelial-mesenchymal transition. Since the stromal microenvironment helps to induce the epithelial-mesenchymal transition, interactions between cancer cells and stroma should be closely examined to predict the tumorigenic phenotype of human bladder cancer cells.

MATERIALS AND METHODS

To investigate differences in the responsiveness of cancer cells to stroma, we combined 3 established human bladder cancer cell lines (high-grade T24 and UM-UC-3 cells, and low-grade papillary RT4 cells) with fetal rat mesenchyme.

RESULTS

Among 3 bladder cancer cell lines, the expression profiles of p63 isoforms were distinct, i.e., p63γ in T24 cells, p63β in UM-UC-3 cells, and p63α in RT4 cells. Tumors formed by T24 cells combined with fetal mesenchyme formed micropapillary-like structures, whereas those formed by T24 cells alone did not. T24 cells combined with fetal mesenchyme showed poor differentiation, e.g., innumerable chromatic atypia in the nuclei, higher levels of chromatic condensation, and increased nucleoli. In contrast, both UM-UC-3 and RT4 cells combined with fetal mesenchyme did not form micropapillary-like structures. Ki-67 and p63 labeling indices were significantly elevated by combining fetal mesenchyme with T24 cells but not with the others.

CONCLUSIONS

By mixing cancer cells with fetal mesenchyme, our data demonstrated that formation of micropapillary-like structures may predict the tumorigenic phenotype of invasive bladder cancer cells. Taken together, distinct expression profiles of p63 isoforms may predict poor outcomes in invasive bladder cancer.

Collagen type IV alpha 1 (COL4A1) and collagen type XIII alpha 1 (COL13A1) produced in cancer cells promote tumor budding at the invasion front in human urothelial carcinoma of the bladder

Current knowledge of the molecular mechanism driving tumor budding is limited. Here, we focused on elucidating the detailed mechanism underlying tumor budding in urothelial cancer of the bladder. Invasive urothelial cancer was pathologically classified into three groups as follows: nodular, trabecular, and infiltrative (tumor budding). Pathohistological analysis of the orthotopic tumor model revealed that human urothelial cancer cell lines MGH-U3, UM-UC-14, and UM-UC-3 displayed typical nodular, trabecular, and infiltrative patterns, respectively. Based on the results of comprehensive gene expression analysis using microarray (25 K Human Oligo chip), we identified two collagens, COL4A1 and COL13A1, which may contribute to the formation of the infiltrative pattern. Visualization of protein interaction networks revealed that proteins associated with connective tissue disorders, epithelial-mesenchymal transition, growth hormone, and estrogen were pivotal factors in tumor cells. To evaluate the invasion pattern of tumor cells in vitro, 3-D collective cell invasion assay using Matrigel was performed. Invadopodial formation was evaluated using Gelatin Invadopodia Assay. Knockdown of collagens with siRNA led to dramatic changes in invasion patterns and a decrease in invasion capability through decreased invadopodia. The in vivo orthotopic experimental model of bladder tumors showed that intravesical treatment with siRNA targeting COL4A1 and COL13A1 inhibited the formation of the infiltrative pattern. COL4A1 and COL13A1 production by cancer cells plays a pivotal role in tumor invasion through the induction of tumor budding. Blocking of these collagens may be an attractive therapeutic approach for treatment of human urothelial cancer of the bladder.

Detection of Intratumor Heterogeneity in Modern Pathology: A Multisite Tumor Sampling Perspective

Current sampling protocols of neoplasms along the digestive tract and in the urinary bladder have to be updated, as they do not respond to the necessities of modern personalized medicine. We show here that an adapted version of multisite tumor sampling (MSTS) is a sustainable model to overcome current deficiencies in digestive and bladder tumors when they are large enough so as to make unaffordable a total sampling. The new method is based on the divide-and-conquer algorithm and includes a slight modification of the MSTS, which proved to be useful very recently in clear cell renal cell carcinoma. This in silico analysis confirms the usefulness of MSTS for detecting intratumor heterogeneity (ITH) in tumors arising in hollow viscera. However, MSTS does not seem to improve routine traditional sampling in detecting tumor budding, extramural venous invasion, and perineural invasion. We conclude that (1) MSTS is the best method for tumor sampling to detect ITH balancing high performance and sustainable cost, (2) MSTS must be adapted to tumor shape and tumor location for an optimal performance.

Tumor Budding, Micropapillary Pattern, and Polyploidy Giant Cancer Cells in Colorectal Cancer: Current Status and Future Prospects

We previously reported that polyploid giant cancer cells (PGCGs) induced by CoCl₂ could form through endoreduplication or cell fusion. A single PGCC formed tumors in immunodeficient mice. PGCCs are also the key contributors to the cellular atypia and associate with the malignant grade of tumors. PGCCs have the properties of cancer stem cells and produce daughter cells via asymmetric cell division. Compared with diploid cancer cells, these daughter cells express less epithelial markers and acquire mesenchymal phenotype with importance in cancer development and progression. Tumor budding is generally recognized to correlate with a high recurrence rate, lymph node metastasis, chemoresistance, and poor prognosis of colorectal cancers (CRCs) and is a good indicator to predict the metastasis and aggressiveness in CRCs. Micropapillary pattern is a special morphologic pattern and also associates with tumor metastasis and poor prognosis. There are similar morphologic features and molecular phenotypes among tumor budding, micropapillary carcinoma pattern, and PGCCs with their budding daughter cells and all of them show strong ability of tumor invasion and migration. In this review, we discuss the cancer stem cell properties of PGCCs, the molecular mechanisms of their regulation, and the relationships with tumor budding and micropapillary pattern in CRCs.

Tumor budding, a novel prognostic indicator for predicting stage progression in T1 bladder cancers

Tumor budding has been defined as an isolated single cancer cell or a cluster composed of fewer than five cancer cells scattered in the stroma. It is a strong predictor for lymph node metastasis in T1 colorectal cancer. We introduced this concept to T1 non‐muscle invasive bladder cancer and evaluated whether tumor budding could have a prognostic impact on the clinical outcome. We identified 121 consecutive patients with newly diagnosed T1 bladder cancer between 1994 and 2014 at Keio University Hospital. All slides were re‐reviewed by a dedicated uropathologist. Budding foci were counted under ×200 magnification. When the number of budding foci was 10 or more, tumor budding was defined as positive. The relationship between tumor budding and clinical outcomes was assessed using a multivariate analysis. The median follow‐up was 52 months. Tumor budding was positive in 21 patients (17.4%). Tumor budding was significantly associated with T1 substaging, tumor architecture and lymphovascular invasion. The 5‐year progression‐free survival rate in T1 bladder cancer patients with tumor budding was 53.8%, which was significantly lower than that in patients without tumor budding (88.4%, P = 0.001). A multivariate Cox regression analysis revealed that tumor budding was independently associated with stage progression (P = 0.002, hazard ratio = 4.90). In a subgroup of patients treated with bacillus Calmette‐Guérin instillation (n = 88), tumor budding was also independently associated with stage progression (P = 0.003, hazard ratio = 5.65). Tumor budding may be a novel indicator for predicting stage progression in T1 bladder cancer, and would likely be easily introduced in clinical practice.