Prognostic significance of substage and WHO classification systems in T1 urothelial carcinoma of the bladder

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.

A single-center retrospective comparison of pT1 substaging methods in bladder cancer

Substaging of T1 urothelial cancer is associated with tumor progression and its reporting is recommended by international guidelines. However, it has not been integrated in risk stratification tools and there is no agreement on the best method to use for its reporting. We aimed to investigate the applicability, interobserver variability, and prognostic value of histological landmark based and micrometric (aggregate linear length of invasive carcinoma (ALLICA), microscopic vs. extensive system, Rete Oncologica Lombarda (ROL) system) substaging methods. A total of 79 patients with the primary diagnosis of T1 urothelial cancer treated with conventional transurethral resection and adjuvant BCG therapy between 2000 and 2020 at the Medical University of Vienna were included. The anatomical and metrical substaging systems were evaluated using agreement rate, Cohen's kappa, Kendall's tau, and Spearman rank correlation. Prognostic value for high-grade recurrence or T2 progression was evaluated in uni- and multivariable analysis. Applicability and reproducibility were good to moderate and varied between substaging methods. Obstacles are mainly due to fragmentation of samples. Anatomical substaging was associated with progression in univariable and multivariable analysis. In our cohort, we could only identify anatomical landmark-based substaging to be prognostic for T2 progression. A major obstacle for proper pathological assessment is fragmentation of samples due to operational procedure. Avoiding such fragmentation might improve reproducibility and significance of pathological T1 substaging of urothelial cancer.

Prognostic value of micrometric substaging in pT1 bladder cancer patients treated with en-bloc transurethral resection

AIMS

We aimed to assess the oncological impact of micrometric extent of invasion in patients with pT1 bladder cancer (BCa) who underwent en-bloc resection for bladder tumour (ERBT).

METHODS AND RESULTS

We retrospectively analysed the records and specimens of 106 pT1 high-grade BCa patients who underwent ERBT. The extent of invasion, such as depth from basal membrane, number of invasive foci, maximum width of invasive focus, muscularis mucosae invasion and infiltration pattern (pattern A: solid sheet-like, nodular or nested growth, pattern B: trabecular, small cluster or single-cell pattern) were evaluated by a single genitourinary pathologist. The end-points were recurrence-free (RFS) and progression-free survival (PFS). Within a median follow-up of 23 months, overall, 36 patients experienced recurrence and 13 patients experienced disease progression. The 2-year PFS differed significantly depending on depth from basal membrane (< 1.3 mm: 94.8% versus ≧ 1.3 mm: 65.2%, P = 0.005), maximum width of invasive focus (< 4 mm: 91.7% versus ≧ 4 mm: 62.3%, P < 0.001), muscularis mucosae (MM) invasion (above MM = 96.1% versus into or beyond MM = 64.8%, P = 0.002) and infiltration pattern (pattern A: 100% versus pattern B: 83.3%, P = 0.037). In a multivariable analysis, MM invasion [hazard ratio (HR) = 4.54, 95% confidence interval (CI) = 1.25-16.5] and maximum width of invasive focus ≧ 4 mm (HR = 4.79, 95% CI = 1.25-16.5) were independent prognostic factors of progression.

CONCLUSIONS

En-bloc resection facilitates the evaluation of pathologic variables that might be useful in predicting disease recurrence and progression. In particular, not only the MM invasion but also the maximum width of invasion focus, reflecting the invasive volume, appear to be reliable prognosticators for disease progression.

Prognosis of patients with T1 low-grade urothelial bladder cancer treated with bacillus Calmette-Guérin immunotherapy

BACKGROUND

The existence and prognosis of T1LG (T1 low-grade) bladder cancer is controversial. Also, because of data paucity, it remains unclear what is the clinical history of bacillus Calmette-Guérin (BCG) treated T1LG tumors and if it differs from other NMIBC (non-muscle-invasive bladder cancer) representatives. The aim of this study was to analyse recurrence-free survival (RFS) and progression-free survival (PFS) in patients with T1LG bladder cancers treated with BCG immunotherapy.

METHODS

A multi-institutional and retrospective study of 2510 patients with Ta/T1 NMIBC with or without carcinoma in situ (CIS) treated with BCG (205 T1LG patients) was performed. Kaplan-Meier estimates and log-rank test for RFS and PFS to compare the survival between TaLG, TaHG, T1LG, and T1HG NMIBC were used. Also, T1LG tumors were categorized into EAU2021 risk groups and PFS analysis was performed, and Cox multivariate model for both RFS and PFS were constructed.

RESULTS

The median follow-up was 52 months. For the T1LG cohort, the estimated RFS and PFS rates at 5-year were 59.3% and 89.2%, respectively. While there were no differences in RFS between NMIBC subpopulations, a slightly better PFS was found in T1LG NMIBC compared to T1HG (5-year PFS; T1LG vs. T1HG: 82% vs. 89%; P<0.001). A heterogeneous classification of patients with T1LG NMIBC was observed when EAU 2021 prognostic model was applied, finding a statistically significant worse PFS in patients classified as high-risk T1LG (5-year PFS; 81.8%) compared to those in intermediate (5-year PFS; 93,4%), and low-risk T1LG tumors (5-year PFS; 98,1%).

CONCLUSIONS

The RFS of T1LG was comparable to other NMIBC subpopulations. The PFS of T1LG tumors was significantly better than of T1HG NMIBC. The EAU2021 scoring model heterogeneously categorized the risk of progression in T1LG tumors and the high-risk T1LG had the worst PFS.

En-bloc resection of non-muscle invasive bladder cancer: does it really make a difference?

PURPOSE OF REVIEW

Transurethral resection of bladder tumour (TURBT) followed by pathology investigation of the obtained specimens is the initial step in the management of urinary bladder cancer (UBC). By following the basic principles of oncological surgery, en-bloc resection of bladder tumour (ERBT) aims to overcome the limitations associated with conventional transurethral resection, and to improve the quality of pathological specimens for a better decision making. The current bulk of evidence provides controversial results regarding the superiority of one technique over the other. The aim of this article is to summarize the recent data and provide evidence on this unanswered question.

RECENT FINDINGS

Despite heterogeneous and controversial data, ERBT seems to have a better safety profile and deliver higher quality pathologic specimens. However, the recent evidence failed to support the hypothesized oncological potential benefits of ERBT in the initial surgical treatment of patients with UBC.

SUMMARY

ERBT has gained increasing interest globally in the past decade. It continues to represent a promising strategy with a variety of features intended to solve the inherent limitations of TURBT. However, the current quality of evidence does not allow solid conclusions to be drawn about its presumed superiority compared with the conventional technique.

Combination of Two T1 Substaging Systems (T1a/b/c and T1m/e) Better Predicts Tumor Outcomes in Patients with T1 High Grade Bladder Cancer

BACKGROUND

T1 substaging is a predictive factor for non-muscle-invasive bladder cancer, and two types of T1 substaging systems (T1a/b/c and T1m/e) are currently in use. However, the predictive ability of both systems is poor, and there is debate over which system is better.

OBJECTIVE

To confirm whether combination of two T1 substaging systems can improve the predictive ability of T1 substaging for tumor outcomes.

METHODS

Patients with primary pT1 high-grade bladder cancer from three centers were included. All tumors were assessed with T1a/b/c and T1m/e substaging. A new variable named COMB was developed in which patients were stratified into T1a/b&T1m, T1a/b&T1e, T1c&T1m or T1c&T1e subgroups. A time-dependent receiver operating characteristic curve (ROC) analysis was used to test whether the accuracy of prediction could be improved with COMB.

RESULTS

A total of 239 patients with primary pT1HG were analyzed. No tumor was T1c&T1m, and therefore, only three types of combinations were evaluated: T1a/b&T1m (62 patients), T1a/b&T1e (124 patients) and T1c&T1e (53 patients). Regardless of all patients or those treated with Re-TURBt and adequate BCG, patients with T1a/b&T1m have the best prognosis, and those with T1c&T1e have the poorest prognosis. The time-dependent ROC showed that, for both recurrence and progression, COMB had a higher AUC than T1a/b/c and T1m/e, regardless of population.

CONCLUSIONS

Compared with either system alone, the combination of two T1 substaging systems improves the predictive ability of T1 substaging for tumor outcomes.

CT-based deep learning radiomics signature for the preoperative prediction of the muscle-invasive status of bladder cancer

Objectives

Although the preoperative assessment of whether a bladder cancer (BCa) indicates muscular invasion is crucial for adequate treatment, there currently exist some challenges involved in preoperative diagnosis of BCa with muscular invasion. The aim of this study was to construct deep learning radiomic signature (DLRS) for preoperative predicting the muscle invasion status of BCa.

Methods

A retrospective review covering 173 patients revealed 43 with pathologically proven muscle-invasive bladder cancer (MIBC) and 130 with non-muscle-invasive bladder cancer (non- MIBC). A total of 129 patients were randomly assigned to the training cohort and 44 to the test cohort. The Pearson correlation coefficient combined with the least absolute shrinkage and selection operator (LASSO) was utilized to reduce radiomic redundancy. To decrease the dimension of deep learning features, Principal Component Analysis (PCA) was adopted. Six machine learning classifiers were finally constructed based on deep learning radiomics features, which were adopted to predict the muscle invasion status of bladder cancer. The area under the curve (AUC), accuracy, sensitivity and specificity were used to evaluate the performance of the model.

Results

According to the comparison, DLRS-based models performed the best in predicting muscle violation status, with MLP (Train AUC: 0.973260 (95% CI 0.9488-0.9978) and Test AUC: 0.884298 (95% CI 0.7831-0.9855)) outperforming the other models. In the test cohort, the sensitivity, specificity and accuracy of the MLP model were 0.91 (95% CI 0.551-0.873), 0.78 (95% CI 0.594-0.863) and 0.58 (95% CI 0.729-0.827), respectively. DCA indicated that the MLP model showed better clinical utility than Radiomics-only model, which was demonstrated by the decision curve analysis.

Conclusions

A deep radiomics model constructed with CT images can accurately predict the muscle invasion status of bladder cancer.

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.

Nonmuscle-invasive bladder cancer, old problems, new insights

PURPOSE OF REVIEW

Nonmuscle-invasive bladder cancer (NMIBC) is the most frequent bladder cancer and represents around 75% of bladder cancers. This review will discuss known challenges and recent advances in staging, grading and treatment stratification based on pathology.

RECENT FINDINGS

Pathological staging and grading in NMIBC remains challenging and different techniques exist. Substaging has been shown to be of prognostic relevance and to help predict treatment response in patients receiving Bacillus Calmette-Guérin (BCG) therapy, which is the treatment of choice for high-grade NMIBC. Recent advances in molecular classification and artificial intelligence were also able to show promising results in the stratification of patients.

SUMMARY

Many challenges in the diagnosis of NMIBC are still unresolved and ask for more prospective research. New technologies, molecular insights and AI will help in the upcoming years to better stratify and manage these patients.

Incidence trends and survival prediction of urothelial cancer of the bladder: a population-based study

Background

The aim of this study is to determine the incidence trends of urothelial cancer of the bladder (UCB) and to develop a nomogram for predicting the cancer-specific survival (CSS) of postsurgery UCB at a population-based level based on the SEER database.

Methods

The age-adjusted incidence of UCB diagnosed from 1975 to 2016 was extracted, and its annual percentage change was calculated and joinpoint regression analysis was performed. A nomogram was constructed for predicting the CSS in individual cases based on independent predictors. The predictive performance of the nomogram was evaluated using the consistency index (C-index), net reclassification index (NRI), integrated discrimination improvement (IDI), a calibration plot and the receiver operating characteristics (ROC) curve.

Results

The incidence of UCB showed a trend of first increasing and then decreasing from 1975 to 2016. However, the overall incidence increased over that time period. The age at diagnosis, ethnic group, insurance status, marital status, differentiated grade, AJCC stage, regional lymph nodes removed status, chemotherapy status, and tumor size were independent prognostic factors for postsurgery UCB. The nomogram constructed based on these independent factors performed well, with a C-index of 0.823 and a close fit to the calibration curve. Its prediction ability for CSS of postsurgery UCB is better than that of the existing AJCC system, with NRI and IDI values greater than 0 and ROC curves exhibiting good performance for 3, 5, and 8 years of follow-up.

Conclusions

The nomogram constructed in this study might be suitable for clinical use in improving the clinical predictive accuracy of the long-term survival for postsurgery UCB.

The Genitourinary Pathology Society Update on Classification of Variant Histologies, T1 Substaging, Molecular Taxonomy, and Immunotherapy and PD-L1 Testing Implications of Urothelial Cancers

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder cancer focusing on important topics of high interest for the practicing surgical pathologist and urologist. This review represents the second of 2 manuscripts ensuing from this effort. Herein, we address the effective reporting of bladder cancer, focusing particularly on newly published data since the last 2016 World Health Organization (WHO) classification. In addition, this review focuses on the importance of reporting bladder cancer with divergent differentiation and variant (subtypes of urothelial carcinoma) histologies and the potential impact on patient care. We provide new recommendations for reporting pT1 staging in diagnostic pathology. Furthermore, we explore molecular evolution and classification, emphasizing aspects that impact the understanding of important concepts relevant to reporting and management of patients.

Feasibility and accuracy of pathological diagnosis in en-bloc transurethral resection specimens versus conventional transurethral resection specimens of bladder tumour: evaluation with pT1 substaging by 10 pathologists

AIMS

En-bloc transurethral resection (TUR) of bladder tumour (ERBT) is designed to provide more accurate pathological diagnosis of specimens than conventional TUR of bladder tumour (cTURBT). Some studies have reported that T1 bladder cancer substage could be a prognostic factor in assessing tumour progression, but such substaging has not been widely adopted because of problems with pathological diagnosis using cTURBT specimens. The aim of this study was to evaluate the possible advantages of en-bloc TUR specimens in T1 substaging following assessment by a panel of 10 pathologists.

METHODS AND RESULTS

We assessed the substages in 123 patients (cTURBT, n = 91; ERBT, n = 32) who were diagnosed with pT1 bladder cancer. We randomly selected 10 ERBT specimens and 10 cTURBT specimens with cancer invasion areas equivalent to those of their corresponding ERBT specimens. Ten pathologists performed pT1 substaging for pT1a/b/c and pT1m/e in 20 patients (cTURBT, n = 10; ERBT, n = 10). We evaluated diagnostic times and rates of diagnostic concordance among these pathologists, comparing cTURBT and ERBT. The median diagnostic times per slide were 87.7 s [interquartile range (IQR) 71.9-109.2 s) for cTURBT and 54.7 s (IQR 46.0-59.6 s) for ERBT (P = 0.009). The rate of diagnostic concordance was significantly better for ERBT specimens. For pT1a/b/c, the median concordance rates were 50% for cTURBT and 80% for ERBT (P = 0.02); for pT1m/e, the median concordance rates were 70% for cTURBT and 90% for ERBT (P = 0.05). For pT1a/b/c, the average κ-values between the pathologist and the standard diagnosis were 0.04 for cTURBT and 0.47 for ERBT.

CONCLUSIONS

The use of ERBT specimens shortened the diagnostic time and minimised interobserver variability for T1 substaging compared with the use of cTURBT specimens.

Prognostic Value of the WHO1973 and WHO2004/2016 Classification Systems for Grade in Primary Ta/T1 Non-muscle-invasive Bladder Cancer: A Multicenter European Association of Urology Non-muscle-invasive Bladder Cancer Guidelines Panel Study

BACKGROUND

In the current European Association of Urology (EAU) non-muscle-invasive bladder cancer (NMIBC) guideline, two classification systems for grade are advocated: WHO1973 and WHO2004/2016.

OBJECTIVE

To compare the prognostic value of these WHO systems.

DESIGN, SETTING, AND PARTICIPANTS

Individual patient data for 5145 primary Ta/T1 NMIBC patients from 17 centers were collected between 1990 and 2019. The median follow-up was 3.9 yr.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariate and multivariable analyses of WHO1973 and WHO2004/2016 stratified by center were performed for time to recurrence, progression (primary endpoint), cystectomy, and duration of survival, taking into account age, concomitant carcinoma in situ, gender, multiplicity, tumor size, initial treatment, and tumor stage. Harrell's concordance (C-index) was used for prognostic accuracy of classification systems.

RESULTS AND LIMITATIONS

The median age was 68 yr; 3292 (64%) patients had Ta tumors. Neither classification system was prognostic for recurrence. For a four-tier combination of both WHO systems, progression at 5-yr follow-up was 1.4% in low-grade (LG)/G1, 3.8% in LG/G2, 7.7% in high grade (HG)/G2, and 18.8% in HG/G3 (log-rank, p < 0.001). In multivariable analyses with WHO1973 and WHO2004/2016 as independent variables, WHO1973 was a significant prognosticator of progression (p <  0.001), whereas WHO2004/2016 was not anymore (p =  0.067). C-indices for WHO1973, WHO2004, and the WHO systems combined for progression were 0.71, 0.67, and 0.73, respectively. Prognostic analyses for cystectomy and survival showed results similar to those for progression.

CONCLUSIONS

In this large prognostic factor study, both classification systems were prognostic for progression but not for recurrence. For progression, the prognostic value of WHO1973 was higher than that of WHO 2004/2016. The four-tier combination (LG/G1, LG/G2, HG/G2, and HG/G3) of both WHO systems proved to be superior, as it divides G2 patients into two subgroups (LG and HG) with different prognoses. Hence, the current EAU-NMIBC guideline recommendation to use both WHO classification systems remains correct.

PATIENT SUMMARY

At present, two classification systems are used in parallel to grade non-muscle-invasive bladder tumors. Our data on a large number of patients showed that the older classification system (WHO1973) performed better in terms of assessing progression than the more recent (WHO2004/2016) one. Nevertheless, we conclude that the current guideline recommendation for the use of both classification systems remains correct, since this has the advantage of dividing the large group of WHO1973 G2 patients into two subgroups (low and high grade) with different prognoses.

Bicentric Retrospective Analysis of en Bloc Resection and Muscularis Mucosae Detection Rate in Non-Muscle Invasive Bladder Tumors: A Real-World Scenario

Introduction

For risk stratification of non-muscle invasive bladder cancer (NMIBC), the depth of stromal invasion can be further classified, where the lamina muscularis mucosae (MM) serves as a reference structure. While the overall identifiability of MM in standard transurethral specimens is low, en bloc resection may help in identification and overall orientation. The aims of this study were to report the detection rate of MM in en bloc resected bladder tumors (ERBT) and to provide real-world information on tissue stability and preservation of en bloc architecture during recovery and processing for histopathologic evaluation.

Methods

Thirty-four ERBT specimens were histologically re-evaluated with regard to MM detectability and structure as well as the presence of en bloc architecture and further histologic features. Associations with tumor size and energy source and within histologic parameters were assessed by standard Pearson's chi-squared analyses and Cramér’s V effect size testing (V).

Results

The first parameter assessed was MM detection rate. In 19 out of 34 samples (56%) MM was detectable: scattered in 9 cases (26%), interrupted in 8 cases (24%) and continuous in 2 cases (6%). The second parameter assessed was preservation of en bloc architecture. In 11 out of 34 samples (32%), en bloc architecture could not be confirmed, and these samples served as a reference group for the detection of MM. Preservation of en bloc architecture was associated with an increased MM detection rate (MM in en bloc preserved 16/23, 70% vs. non-preserved 3/11, 27%; p = 0.020; V = 0.398) and with tumor size (p = 0.005; V = 0.595). Medium-sized tumors (1.1–2 cm) were best preserved. The choice of energy source did not show relevant association with en bloc architecture (p = n.s.).

Conclusions

In line with recent publications, ERBT increases the MM detection rate considerably. However, a third of the ERBT specimens lost en bloc architecture during sample recovery and processing. Tumor size is a relevant factor, with optimal architecture preservation between 1 and 2 cm. Optimizing resection techniques, recovery, transport, and diagnostic processing of ERBT samples is warranted to verify the diagnostic value of MM-based substaging.

Holmium Laser En-bloc Resection Versus Conventional Transurethral Resection of Bladder Tumors for Treatment of Non-muscle-invasive Bladder Cancer: A Randomized Clinical Trial

BACKGROUND

En-bloc resection of bladder tumors achieves complete tumor removal, improves the quality of resection, decreases perioperative complication, and potentially improves recurrence rates.

OBJECTIVE

To assess the efficacy and safety of holmium laser en-bloc resection (HolERBT) versus conventional transurethral resection of bladder tumor (cTURBT).

DESIGN, SETTING, AND PARTICIPANTS

Between September 2015 and September 2018, 100 patients with non-muscle-invasive bladder cancer were randomly allocated to cTURBT or HolERBT.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was detection of residual tumor in reTURBT specimens at 4 wk after the primary resection. Operative parameters, specimen quality, perioperative complications, and recurrence-free survival (RFS) were compared. Independent sample t tests, χ² tests, and Kaplan-Meier curves were used, as appropriate.

RESULTS AND LIMITATIONS

The patient and tumor baseline characteristics were comparable between the groups. Residual tumors were detected in 7% and 27.7% of cases after HolERBT and cTURBT, respectively (p=0.01). Detrusor muscle was sampled in 98% of HolERBT and 62% of cTURBT cases (p<0.001). Lamina propria invasion substaging was feasible in only 68.2% of HolERBT and 18.4% of cTURBT cases (p<0.001). Following HolERBT, catheterization time (p<0.001) and hospital stay (p=0.001) were shorter when compared to cTURBT. Immediate postoperative instillation of chemotherapy in indicated cases was feasible for 100% of the HolERBT group and 91.5% of the cTURBT group (p=0.04). After follow-up of 20 ± 9.9 mo (13-36), RFS was 31.76 mo (95% confidence interval [CI] 28.67-34.86) in the HolERBT group and 28.25 mo (95% CI 24.87-31.64) in the cTURBT group (hazard ratio 0.43, 95% CI 0.17-1.1; p=0.07). However, this study was not powered to detect a difference in RFS.

CONCLUSIONS

Compared to cTURBT, HolERBT is a safer procedure for bladder tumor resection. It fulfills the oncological criteria of optimized resection with less residual tumor and better specimen quality.

PATIENT SUMMARY

En-bloc resection of bladder cancer tumors using a holmium laser is safer than the conventional technique. It has the advantages of less residual tumor and better specimen quality, with a similar tumor recurrence rate. This study is registered at ClinicalTrials.gov as NCT02555163.

Comparative Application of Different Substaging Techniques for Non-Muscle Invasive Urothelial Carcinoma

To evaluate the diagnostic performance and clinical significance of 4 systems of substaging cases with non-muscle invasive urothelial bladder carcinoma. In addition 4 cutoff measures were evaluated for prediction of muscularis-mucosa invasion. Four substaging systems were applied to 57 NMIBC cases to assess which of these reported methods correlates best with recurrence and progression. On univariate regression analysis patients having tumor size more than 3 cm, solid tumor architecture, high grade, substage B, substage T1e, substage ROL 2 and Tumor depth more than 1 mm were associated with higher recurrence. On multivariate analysis all the four substaging systems, tumor size, grade and tumor type had significant prognostic value for recurrence. Regarding progression only the metric substaging method was associated with tumor progression (p = 0.04). However, on univariate and multivariate regression analysis none of the substaging systems showed prognostic significance and only solid tumor architecture and CIS had significant prognostic value for tumor progression. The ROC curve analysis showed that 1 mm depth of invasion had the best accuracy for detection of muscularis-mucosa invasion (80.2%). Using 1 mm cutoff in measuring the depth and 0.5 mm for the diameter of infiltration may provide clinically relevant information to guide a more personalized therapy for NMIBC. Inclusion of both measures in addition to other histopathologic variables may aid in the development of a scoring system.

Application of nomograms in the prediction of overall survival and cancer-specific survival in patients with T1 high-grade bladder cancer

To predict survival outcomes for individual patients with clinical T1 high-grade (T1HG) bladder cancer (BC), data from the Surveillance Epidemiology and End Results (SEER) database were analyzed in the present study. The data of 6,980 cases of T1HG BC between 2004 and 2014 were obtained from the SEER database. Uni- and multivariate Cox analyses were performed to identify significant prognostic factors. Subsequently, prognostic nomograms for predicting 3- and 5-year overall survival (OS) and cancer-specific survival (CSS) rates were constructed based on the SEER database. Clinical information from the SEER database was divided into internal and external groups and used to validate the nomograms. In addition, calibration plot diagrams and concordance indices (C-indices) were used to verify the predictive performance of the nomogram. A total of 6,980 patients were randomly allocated to the training cohort (n=4,886) or the validation cohort (n=2094). Univariate and multivariate Cox analyses indicated that age, ethnicity, tumor size, marital status, radiation and surgical status were independent prognostic factors. These characteristics were used to establish nomograms. The C-indices for OS and CSS rate predictions for the training cohort were 0.707 (95% CI, 0.693–0.721) and 0.700 (95% CI, 0.679–0.721), respectively. Internal and external calibration plot diagrams exhibited an excellent consistency between actual survival rates and nomogram predictions, particularly for 3- and 5-year OS and CSS. The significant prognostic factors in patients with T1HG BC were age, ethnicity, marital status, tumor size, status of surgery and use of radiation. In the present study, a nomogram was developed that may serve as an effective and convenient evaluation tool to help surgeons perform individualized survival evaluations and mortality risk determination for patients with T1HG BC.

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.

Three-dimensional histopathological reconstruction of bladder tumours

BACKGROUND

Histopathological analysis is the cornerstone in bladder cancer (BCa) diagnosis. These analysis suffer from a moderate observer agreement in the staging of bladder cancer. Three-dimensional reconstructions have the potential to support the pathologists in visualizing spatial arrangements of structures, which may improve the interpretation of specimen. The aim of this study is to present three-dimensional (3D) reconstructions of histology images.

METHODS

En-bloc specimens of transurethral bladder tumour resections were formalin fixed and paraffin embedded. Specimens were cut into sections of 4 μm and stained with Hematoxylin and Eosin (H&E). With a Phillips IntelliSite UltraFast scanner, glass slides were digitized at 20x magnification. The digital images were aligned by performing rigid and affine image alignment. The tumour and the muscularis propria (MP) were manually delineated to create 3D segmentations. In conjunction with a 3D display, the results were visualized with the Vesalius3D interactive visualization application for a 3D workstation.

RESULTS

En-bloc resection was performed in 21 BCa patients. Per case, 26-30 sections were included for the reconstruction into a 3D volume. Five cases were excluded due to export problems, size of the dataset or condition of the tissue block. Qualitative evaluation suggested an accurate registration for 13 out of 16 cases. The segmentations allowed full 3D visualization and evaluation of the spatial relationship of the BCa tumour and the MP.

CONCLUSION

Digital scanning of en-bloc resected specimens allows a full-fledged 3D reconstruction and analysis and has a potential role to support pathologists in the staging of BCa.

En bloc resection improves the identification of muscularis mucosae in non-muscle invasive bladder cancer

PURPOSE

The T1 substage, according to the relationship between muscularis mucosae (MM) and tumors, is a promising prognostic factor for T1 bladder cancer. However, the identification rate of MM is low in specimens, and it is, therefore, not widely used in clinical practice. In this study, we investigated whether en bloc resection of non-muscle invasive bladder cancer (NMIBC) could improve the identification of muscularis mucosae (MM), which may further accurate identification of the T1 substage.

PATIENTS AND METHODS

Specimens from 158 patients with primary NMIBC were retrospectively reviewed by two independent pathologists to assess the presence of MM and stratify the T1 substage. Of 158 specimens, 70 specimens were obtained via TURBt with a plasma kinetic loop and 88 were obtained via front-firing potassium-titanyl-phosphate (KTP) green-light laser en bloc resection. Univariable and multivariable logistic regression models were used to analyze the relationship between the clinical characteristics and the presence of MM.

RESULTS

The mean age was 58.22 years (range 18-85 years). Multivariable logistic regression analysis showed that the KTP laser resection method was associated with the presence of MM in specimens (P = 0.008). In addition, tumors with smaller sizes, which could also be en bloc resected with TURBt (e.g., ≤1 cm), had a higher presence of MM (P = 0.047).

CONCLUSIONS

En bloc resection improves the identification rate of MM, which may enhance the accurate identification of the T1 substage.

Urinary Bladder Pathology: World Health Organization Classification and American Joint Committee on Cancer Staging Update

Context.—

Since the publication of the previous World Health Organization (WHO) Classification of Tumours on the Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs in 2004, significant new knowledge has been generated regarding the pathology and genetics of bladder neoplasia. Publication of the 2016 WHO “Blue Book” has codified that new data into updated recommendations for classification and prognostication. Similarly, the recent release of the 8th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, which was implemented in January 2018, has also addressed staging criteria for bladder cancer in several unique settings to clarify their application.

Objective.—

To highlight subtle changes within the recent WHO and AJCC publications that may affect daily surgical pathology practice.

Data Sources.—

Peer-reviewed published literature, the 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs, and the 8th edition of the AJCC Cancer Staging Manual were reviewed.

Conclusions.—

Selected changes and/or clarifications are discussed and include classification of flat and papillary urothelial neoplasia, select variant patterns of invasive urothelial carcinoma, staging of invasive carcinoma in bladder diverticula, and staging of carcinomas involving the prostate gland.

Metric substage according to micro and extensive lamina propria invasion improves prognostics in T1 bladder cancer

BACKGROUND

Reliable prognosticators for T1 bladder cancer (T1BC) are urgently needed.

OBJECTIVE

To compare the prognostic value of 2 substage systems for T1BC in patients treated by transurethral resection (TUR) and adjuvant bacillus Calmette-Guérin therapy.

DESIGN, SETTING, AND PARTICIPANTS

The slides of 601 primary T1BCs from four institutes were reviewed by 2 uropathologists and substaged according to 2 classifications: metric substage according to T1 microinvasive (T1m-lamina propria invasion <0.5mm) and T1 extensive invasive (pT1e-invasion ≥ 0.5mm), and according to invasion of the muscularis mucosae (MM) (T1a-invasion above or into MM/T1b).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariable analyses for progression-free (PFS) and cancer-specific survival (CSS) were performed including substage, size, multiplicity, carcinoma in situ, sex, age, WHO-grade 1973, and WHO-grade 2004 as variables.

RESULTS

Median follow-up was 5.9 years (interquartile range: 3.3-9.0). Progression to T2BC was observed in 148 (25%) patients and 94 (16%) died of BC. The MM was not present at the invasion front in 135 (22%) of tumors. Slides were substaged as follows: 213 T1m and 388 T1e and 281 T1a and 320 T1b. On multivariable analysis, T1m/e substage and WHO 1973 grade were the strongest prognosticators for PFS (hazard ratio [HR] = 3.8 and HR = 1.8) and CSS (HR = 2.7 and HR = 2.6), respectively. Other prognostic factors for CSS were age (HR = 1.03), and tumor size (HR = 1.8). Substage according to MM-invasion was not significant. Our study was limited by its retrospective design and that standard re-TUR was not performed if TUR was macroscopically complete and muscularis propria was present in resected specimens.

CONCLUSIONS

Metric substaging of T1BC was possible in all cases of 601 T1BC patients and it was a strong independent prognosticator of both PFS and CSS.

The World Health Organization 1973 classification system for grade is an important prognosticator in T1 non-muscle-invasive bladder cancer

OBJECTIVES

To compare the prognostic value of the World Health Organization (WHO) 1973 and 2004 classification systems for grade in T1 bladder cancer (T1-BC), as both are currently recommended in international guidelines.

PATIENTS AND METHODS

Three uro-pathologists re-revised slides of 601 primary (first diagnosis) T1-BCs, initially managed conservatively (bacille Calmette-Guérin) in four hospitals. Grade was defined according to WHO1973 (Grade 1-3) and WHO2004 (low-grade [LG] and high-grade [HG]). This resulted in a lack of Grade 1 tumours, 188 (31%) Grade 2, and 413 (69%) Grade 3 tumours. There were 47 LG (8%) vs 554 (92%) HG tumours. We determined the prognostic value for progression-free survival (PFS) and cancer-specific survival (CSS) in Cox-regression models and corrected for age, sex, multiplicity, size and concomitant carcinoma in situ.

RESULTS

At a median follow-up of 5.9 years, 148 patients showed progression and 94 died from BC. The WHO1973 Grade 3 was negatively associated with PFS (hazard ratio [HR] 2.1) and CSS (HR 3.4), whilst WHO2004 grade was not prognostic. On multivariable analysis, WHO1973 grade was the only prognostic factor for progression (HR 2.0). Grade 3 tumours (HR 3.0), older age (HR 1.03) and tumour size >3 cm (HR 1.8) were all independently associated with worse CSS.

CONCLUSION

The WHO1973 classification system for grade has strong prognostic value in T1-BC, compared to the WHO2004 system. Our present results suggest that WHO1973 grade cannot be replaced by the WHO2004 classification in non-muscle-invasive BC guidelines.

Challenges in Pathologic Staging of Bladder Cancer: Proposals for Fresh Approaches of Assessing Pathologic Stage in Light of Recent Studies and Observations Pertaining to Bladder Histoanatomic Variances

The paradigm of pathologic stage (pT) categorization in bladder cancer remains the depth of invasion into the different histologic layers of the bladder wall. However, the approaches to assigning pT stage category toward an enhanced outcome stratification have been marked by challenges and innovations, due in part to our growing appreciation of the surprisingly perplexing bladder histoanatomy. Upstaging of pT1 tumors after radical cystectomy is substantial and underscores the potential value of pT1 substaging in transurethral resection (TUR) specimens. The 2017 American Joint Committee on Cancer tumor-node-metastasis system recommends pT1 substaging but recognizes the need to optimize the approach. Over the years, the cut-off for microinvasion has been significantly lowered to 0.5 mm and is now a promising scheme for pT1 (micrometric) substaging. Unlike the micrometric approach, histoanatomic substaging using muscularis mucosae (MM) and vascular plexus as landmarks is less feasible in TUR specimens and inconsistent in stratifying the outcome of pT1 tumors. The lamina propria possesses inherent variations in depth, MM, and vascular plexus dispositions that should be factored in future pT1 substaging proposals. Histoanatomic variations among the bladder regions also occur, and studies suggest that trigone and bladder neck cancers may have more adverse outcomes. The muscularis propria (MP), besides being the essential histologic landmark for assigning pT2 stage category, is also considered a surrogate for the adequacy of TUR, furthering the importance of identifying its presence in TUR specimens. MP, however, may be mimicked by hyperplastic or isolated MP-like MM muscle bundles in the lamina propria with overstaging implications, and caution should be exercised in distinguishing these 2 muscle types morphologically and immunohistochemically. Presence of additional superficial MP unique from the detrusor muscle proper may also complicate staging at the trigone and ureter insertion sites. With regard to the depth of MP invasion, large and multicenter studies have reaffirmed the prognostic significance of pT2a/b subcategories. It is revealed that there are at least 3 ways used to demarcate the irregular MP to perivesical soft tissue junction, and use of a common criterion indicates improvement in pT2b/pT3a staging reproducibility. Although studies have shown significantly poorer outcome in pT3b compared with pT3a tumors, this designation has a substantial reliance on the prosector's gross assessment of perivesical soft tissue invasion which if performed incorrectly may lead to staging inaccuracy of pT3 tumors. The 8th edition of the American Joint Committee on Cancer has updated the staging schema for bladder cancers with concomitant prostatic stromal invasion and cancers within bladder diverticula. Because of 2 possible pT designations, prostatic stromal invasion in TUR specimens should not be automatically staged as either pT4a or pT2 (urethral). Recent data support that bladder cancer invading into the seminal vesicle has comparable outcome to pT4b tumors. Interestingly, several studies in pT4a tumors, which are staged based on sex-specific organs, have shown poorer outcome in females than males after radical cystectomy, and while there are possibly several reasons, they may also include anatomic factors. Despite the progress has been made, work remains to be done to inform future bladder cancer pT category definitions and their reproducibility in application and prognostication.