Stalk versus base invasion in pT1 papillary cancers of the bladder: improved substaging system predicting the risk of progression

A Systematic Review on the Current Landscape of T1 Bladder Cancer Substaging

OBJECTIVE

To conduct a systematic review on the current state of T1 bladder tumor substaging. These neoplasms display significant heterogeneity in oncological behavior and prognosis, leading to the proposal of various substaging methods. Our aim was to investigate the potential diagnostic and prognostic value of substaging in stage T1 bladder cancer for better oncologic outcomes.

METHODS

A literature search using MEDLINE, EMBASE and Cochrane Library databases was conducted in March 2024 to identify relevant studies on T1 urothelial bladder cancer staging. A systematic review of included articles was performed following the PRISMA guideline statement. Literature search was conducted in English.

RESULTS

Overall, 63 studies published between 1990 and 2024 were included for final review including a total number of 8207 bladder tumor patients subject to T1 substaging. Various substaging methods have been developed, broadly classified into histometric (anatomy-based) and micrometric (semiquantitative) techniques. Advanced stages have been consistently associated with worse prognosis and need for a more radical therapeutic approach. A standardized, validated, unified substaging report system is lacking.

CONCLUSIONS

T1 substaging is a strong predictor of oncologic outcomes. Micrometric methods seem to be more reproducible and precise than histometric techniques in terms of feasibility and prognostic value. Standardization and validation of the technique could potentially enhance the bladder cancer treatment algorithm. We would like to provide an explanation regarding why our systematic review was not prospectively registered in the PROSPERO database. Initially, this review was conceived as part of a doctoral thesis (PhD) project, and there was no intention to publish it. Although we strictly adhered to the PRISMA guidelines from the beginning, the decision to publish the review was made only after most of the data had been extracted. At that point, retrospectively registering it in PROSPERO would have been somewhat unethical, which is why we chose not to register it. We fully recognize the importance of actively registering systematic reviews, as it is the proper and ethical way to proceed in these cases. We remain committed to transparency and best practices in research and believe that prospective registration is crucial for ensuring the integrity and credibility of systematic reviews.

Contrast-enhanced computed tomography-based radiomics nomogram for predicting HER2 status in urothelial bladder carcinoma

Objective

To evaluate the performance of a clinical-radiomics model based on contrast-enhanced computed tomography (CE-CT) in assessing human epidermal growth factor receptor 2 (HER2) status in urothelial bladder carcinoma (UBC).

Methods

From January 2022 to December 2023, 124 patients with UBC were classified into the training (n=100) and test (n=24) sets. CE-CT scans were performed on the patients. Univariate and multivariate analyses were conducted to identify independent predictors of HER2 status in patients with UBC. We employed eight machine learning algorithms to establish radiomic models. A clinical-radiomics model was developed by integrating radiomic signatures and clinical features. Receiver operating characteristic curves and decision curve analysis (DCA) were generated to evaluate and validate the predictive capabilities of the models.

Results

Among the eight classifiers, the random forest radiomics model based on CE-CT demonstrated the highest efficacy in predicting HER2 status, with area under the curve (AUC) values of 0.880 (95% CI: 0.813-0.946) and 0.814 (95% CI: 0.642-0.986) in the training and test sets, respectively. In the training set, the clinical-radiomics model achieved an AUC of 0.935, an accuracy of 0.870, a sensitivity of 0.881, and a specificity of 0.854. In the test set, the clinical-radiomics model achieved an AUC of 0.857, an accuracy of 0.760, a sensitivity of 0.643, and a specificity of 0.900. DCA analysis indicated that the clinical-radiomics model provided good clinical benefit.

Conclusion

The radiomics nomogram demonstrates good diagnostic performance in predicting HER2 expression in patients with UBC.

A Nomogram of MRI Features to Assess Muscle Invasion in VI-RADS 2 Tumors With Stalk

BACKGROUND

Vesical Imaging-Reporting and Data System (VI-RADS) is widely used to assess the muscle-invasive status of bladder cancer. However, the current classification efficacy of VI-RASD 2 tumors of stalk is unsatisfactory.

PURPOSE

To develop a nomogram to assess muscle-invasive bladder cancer (MIBC) in VI-RADS 2 tumors with stalk.

STUDY TYPE

Retrospective.

POPULATION

A total of 186 patients (age: 67.8 ± 12.7 years) with 15.1% females, divided randomly into a training cohort (N = 130) and validation cohort (N = 56).

FIELD STRENGTH/SEQUENCE

3-T, T2-weighted imaging (turbo spin-echo), diffusion-weighted imaging (breathing-free spin-echo), and dynamic contrast-enhanced imaging (gradient-echo).

ASSESSMENT

Twenty-one MRI features of tumors and stalks were developed from training cohort. The mean apparent diffusion coefficient (ADC) values of the tumor, stalk, and psoas muscles were calculated from the three circular regions of interest. The normalized T value = mean ADC tumor mean ADC muscle . The normalized ST value = mean ADC stalk mean ADC tumor . Three readers assessed the morphology of tumors and stalks.

STATISTICAL TESTS

The final features of nomogram were selected by univariable logistic and the least absolute shrinkage and selection operator (LASSO) regression. The performance of the nomogram was assessed by the receiver operating characteristic (ROC) curve, calibration, and decision curve analysis.

RESULTS

In VI-RADS 2 tumors with stalk, tumor size over 3 cm, increased stalk width, stalk morphology, decreased normalized T value, and increased normalized ST value were selected as the risk factors for MIBC. The AUC, accuracy, sensitivity, and specificity of the nomogram to assess MIBC were 0.969 (95% CI: 0.941-0.997), 92.3%, 94.1%, and 92.0% in training cohort and 0.940 (95% CI: 0.859-1.000), 89.3%, 75.0%, and 91.7% in validation cohort.

DATA CONCLUSION

This study constructed a nomogram for preoperative assessment of MIBC and modifying the current VI-RADS.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer: Working Group 3: Subcategorization of T1 Bladder Cancer

Emerging data on T1 bladder cancer subcategorization (aka substaging) suggests a correlation with oncological outcomes. The International Society of Urological Pathology (ISUP) organized the 2022 consensus conference in Basel, Switzerland to focus on current issues in bladder cancer and tasked working group 3 to make recommendations for T1 subcategorization in transurethral bladder resections. For this purpose, the ISUP developed and circulated a survey to their membership querying approaches to T1 bladder cancer subcategorization. In particular, clinical relevance, pathological reporting, and endorsement of T1 subcategorization in the daily practice of pathology were surveyed. Of the respondents of the premeeting survey, about 40% do not routinely report T1 subcategory. We reviewed literature on bladder T1 subcategorization, and screened selected articles for clinical performance and practicality of T1 subcategorization methods. Published literature offered evidence of the clinical rationale for T1 subcategorization and at the conference consensus (83% of conference attendants) was obtained to report routinely T1 subcategorization of transurethral resections. Semiquantitative T1 subcategorization was favored (37%) over histoanatomic methods (4%). This is in line with literature findings on practicality and prognostic impact, that is, a shift of publications from histoanatomic to semiquantitative methods or by reports incorporating both methodologies is apparent over the last decade. However, 59% of participants had no preference for either methodology. They would add a comment in the report briefly stating applied method, interpretation criteria (including cutoff), and potential limitations. When queried on the terminology of T1 subcategorization, 34% and 20% of participants were in favor of T1 (microinvasive) versus T1 (extensive) or T1 (focal) versus T1 (nonfocal), respectively.

Learning from the past and present to change the future: Endoscopic management of upper urinary tract urothelial carcinoma

Current guidelines recommend endoscopic management (EM) for patients with low-risk upper urinary tract urothelial carcinoma, as well as those with an imperative indication. However, regardless of the tumor risk, radical nephroureterectomy is still mainly performed worldwide despite the benefits of EM, such as renal function maintenance, no hemodialysis requirement, and treatment cost reduction. This might be explained by the association of EM with a high risk of local recurrence and progression. Furthermore, the need for rigorous patient selection and close surveillance following EM may be relevant. Nevertheless, recent developments in diagnostic modalities, pathological evaluation, surgical devices and techniques, and intracavitary regimens have been reported, which may contribute to improved risk stratification and treatments with superior oncological outcomes. In this review, considering recent advances in endourology and oncology, we propose novel treatment strategies for optimal EM.

An update on computational pathology tools for genitourinary pathology practice: A review paper from the Genitourinary Pathology Society (GUPS)

Machine learning has been leveraged for image analysis applications throughout a multitude of subspecialties. This position paper provides a perspective on the evolutionary trajectory of practical deep learning tools for genitourinary pathology through evaluating the most recent iterations of such algorithmic devices. Deep learning tools for genitourinary pathology demonstrate potential to enhance prognostic and predictive capacity for tumor assessment including grading, staging, and subtype identification, yet limitations in data availability, regulation, and standardization have stymied their implementation.

Update on Flat and Papillary Urothelial Lesions: Genitourinary Pathology Society Consensus Recommendations

The reporting recommendations on "flat and papillary urothelial neoplasia," published in 2 position articles by the Genitourinary Pathology Society in July 2021, was a collective contribution of 38 multidisciplinary experts aiming to clarify nomenclature, classification of flat and papillary urothelial neoplasia and controversial issues. In this review, we discuss some of these recommendations including nomenclature, practical approaches, and their importance for clinical practice.

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

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

News in the classification of WHO 2022 bladder tumors

The fifth-edition of World Health Organization (WHO) Classification of Tumors series for urinary and male genital tract tumors has been published, six years later the fourth-edition. In these years, new treatment approaches have been implemented and new molecular data on urological cancers are known.

Morphology remains the groundwork for taxonomy of the urinary tract tumors. However, a molecular approach to classification of urothelial carcinomas and the management of selected neoplasms with new therapeutic modalities such as immunotherapy are emerging. More data are needed for the application of these advances in routine pathology practice and patient management.

The 2022 World Health Organization (WHO) Classification of Tumors of the Urinary System and Male Genital Organs represents an update in classification on urinary tract tumors. It also offers new insights with regards to the grading of heterogeneous non-invasive urothelial neoplasms, the definition of inverted neoplasms, the grading of invasive urothelial carcinomas, the diversity of morphological appearance of urothelial carcinomas, the definition of precursor lesions and the lineage of differentiation of the tumors.

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

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

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.

The Genitourinary Pathology Society Update on Classification and Grading of Flat and Papillary Urothelial Neoplasia With New Reporting Recommendations and Approach to Lesions With Mixed and Early Patterns of Neoplasia

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder neoplasia with a focus on issues relevant to the practicing surgical pathologist for the understanding and effective reporting of bladder cancer, emphasizing particularly on the newly accumulated evidence post-2016 World Health Organization (WHO) classification. The work is presented in 2 manuscripts. Here, in the first, we revisit the nomenclature and classification system used for grading flat and papillary urothelial lesions centering on clinical relevance, and on dilemmas related to application in routine reporting. As patients of noninvasive bladder cancer frequently undergo cystoscopy and biopsy in their typically prolonged clinical course and for surveillance of disease, we discuss morphologies presented in these scenarios which may not have readily applicable diagnostic terms in the WHO classification. The topic of inverted patterns in urothelial neoplasia, particularly when prominent or exclusive, and beyond inverted papilloma has not been addressed formally in the WHO classification. Herein we provide a through review and suggest guidelines for when and how to report such lesions. In promulgating these GUPS recommendations, we aim to provide clarity on the clinical application of these not so uncommon diagnostically challenging situations encountered in routine practice, while also importantly advocating consistent terminology which would inform future work.

Prognosis of patients with T1 bladder cancer after en bloc transurethral resection of bladder tumor stratified by invasion to the level of the muscularis mucosa

PURPOSE

To evaluate the prognosis of patients with pT1 bladder cancer who underwent en bloc resection of bladder tumors (ERBTs), stratified by invasion to the muscularis mucosa (MM) level.

METHODS

Among 64 specimens obtained by ERBT with bipolar energy from patients with pT1 bladder cancer, MM was detected in 61 specimens. Thus, 61 specimens were included in this retrospective study. Patients were stratified by invasion to the MM level (pT1a, invasion above the MM level; pT1b, invasion within the MM level; and pT1c, invasion beyond the MM level). In specimens with discontinuous MM, invasion to the MM level was predicted from the dispersed MM in the specimen. The primary endpoints were progression-free survival (PFS) and cancer-specific survival (CSS).

RESULTS

Progression occurred in 2/39 patients with pT1a (5.1%), 1/6 patients with pT1b (16.7%), and 6/16 patients with pT1c cancer (37.5%). Cancer death occurred in 1/39 patients with pT1a (2.6%), 0/7 patients with pT1b, and 3/16 patients with pT1c cancer (18.8%). Patients with pT1a or pT1b cancer had a significantly better prognosis than those with pT1c cancer. On univariate analysis, tumor size ≥ 3 cm and pT1c were significantly associated with shorter PFS. On multivariate analysis, only pT1c was independently associated with shorter PFS.

CONCLUSION

This is the first study evaluating the prognosis by T1 substaging based on invasion to the MM level using ERBT specimens. ERBT provided high-quality specimens for diagnosing the MM and showed poor prognosis in pT1c bladder cancer. ERBT could be an appropriate surgical approach for an accurate diagnosis and prognosis of the T1 bladder cancer substage.

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.

Updates in Staging and Reporting of Genitourinary Malignancies

CONTEXT.—

The 8th edition of the American Joint Committee on Cancer (AJCC) staging manual changed the tumor, node, metastasis (TNM) classification systems of genitourinary malignancies in 2017. However, some of the changes appear not well appreciated or recognized by practicing pathologists.

OBJECTIVE.—

To review the major changes compared with the 7th edition in cancers of the prostate, penis, testis, bladder, urethra, renal pelvis/ureter, and kidney and discuss the challenges that pathologists may encounter.

DATA SOURCES.—

Peer-reviewed publications and the 8th and 7th editions of the AJCC Cancer Staging Manual.

CONCLUSIONS.—

This article summarizes the updated staging of genitourinary malignancies, specifically highlighting changes from the 7th edition that are relevant to the pathologic staging system. Pathologists should be aware of the updates made in hopes of providing clarification and the remaining diagnostic challenges associated with these changes.

pT1 high-grade bladder cancer: histologic criteria, pitfalls in the assessment of invasion, and substaging

Most patients with bladder carcinoma are diagnosed with non-muscle-invasive disease, stage Ta, and pT1. Stage remains as the single most important prognostic indicator in urothelial carcinoma. Among the pT1 bladder cancer patients, recurrence and progression of disease occur in 50% and 10%, respectively. The identification of high-risk patients within the pT1 subgroup remains an important clinical goal and an active field of research. Substaging of pT1 disease has been claimed as important histologic discriminator by the 2016 World Health Organization (WHO) classification of the genitourinary tract tumors and by the 8th edition of the American Joint Committee on Cancer (AJCC) staging manual supporting its implementation in clinical practice. Interobserver variation in pT1 diagnosis and the associated pitfalls in pT1 assessment are the critical pathological issues. The aim of this review paper is to provide the practicing pathologist with the state of the art of morphological and immunohistochemical features useful for the diagnosis of early invasive bladder carcinomas, including practical clues on how to avoid relevant interpretative pitfalls, and to summarize the current status of pT1 substaging.

Staging of bladder cancer

Urothelial carcinoma of the urinary bladder is a heterogeneous disease with multiple possible treatment modalities and a wide spectrum of clinical outcome. Treatment decisions and prognostic expectations hinge on accurate and precise staging, and the recently published American Joint Committee on Cancer (AJCC) Staging Manual, 8th edition, should be the basis for staging of urinary bladder tumours. It is unfortunate that the International Union Against Cancer (UICC) 8th edition failed to incorporate new data which is considered in the AJCC 8th edition. Thus, the AJCC 8th edition is the focus of this review. Several critical changes and clarifications are made by the AJCC 8th edition relative to the 7th edition. Although the most obvious changes in the 8th edition are in the N (i.e. perivesical lymph node involvement now classified as N1) and M (i.e. M1 is subdivided into M1a and M1b) categories, several points are clarified in the T category (e.g. substaging of pT1 should be attempted). Further optimisation, however, is required. No particular method of substaging pT1 is formally recommended. In this review, these modifications are discussed, as well as points, which require further study and optimisation.