Clinical outcomes after intravesical bacillus Calmette-Guérin for the highest-risk non-muscle-invasive bladder cancer newly defined in the Japanese Urological Association Guidelines 2019

Validation of non-muscle-invasive bladder cancer risk stratification updated in the 2021 European Association of Urology guidelines

Objective

The objective of this study is to validate the predictive ability of the 2021 European Association of Urology (EAU) risk model compared to that of existing risk models, including the 2019 EAU model and risk scoring tables of the European Organization for Research and Treatment of Cancer, Club Urologico Espanol de Tratamiento Oncologico, and Japanese Nishinihon Uro-oncology Extensive Collaboration Group.

Patients and methods

This retrospective multi-institutional database study included two cohorts-3024 patients receiving intravesical bacillus Calmette-Guerin (BCG) treatment (BCG cohort) and 789 patients not receiving BCG treatment (non-BCG cohort). The Kaplan-Meier estimate and log-rank test were used to visualize and compare oncological survival outcomes after transurethral surgery among the risk groups. Harrell's concordance index (C-index) was used to evaluate the predictive ability of the models.

Results

We observed a risk shift from the 2019 EAU risk grouping to the 2021 EAU risk grouping in a substantial number of patients. For progression, the C-index of the 2021 EAU model was significantly higher than that of the 2019 EAU model in both the BCG (0.617 vs. 0.572; P = 0.011) and non-BCG (0.718 vs. 0.560; P < 0.001) cohorts. According to the 2021 EAU model, 731 (24%) and 130 (16%) patients in the BCG and non-BCG cohorts, respectively, were considered to have a very high risk. Survival analysis showed no significant differences among the five very high-risk subgroups in both cohorts. A major limitation was potential selection bias owing to the retrospective nature of this study.

Conclusions

The updated 2021 EAU model showed better stratification than the three existing risk models, especially for progression, in both cohorts, determining the most appropriate postoperative treatment and identifying patients requiring intensified surveillance or early cystectomy.

Recent advancements in the diagnosis and treatment of non-muscle invasive bladder cancer: Evidence update of surgical concept, risk stratification, and BCG-treated disease

In the management of non-muscle invasive bladder cancer (NMIBC), disease progression and long-term control are determined by the intensity of delivered treatment and surveillance and the cancer cells' biological nature. This requires risk stratification-based postoperative management, such as intravesical instillation of chemotherapy drugs, Bacillus Calmette-Guérin (BCG), and radical cystectomy. Advancements in mechanical engineering, molecular biology, and surgical skills have evolved the clinical management of NMIBC. In this review, we describe the updated evidence and perspectives regarding the following aspects: (1) advancements in surgical concepts, techniques, and devices for transurethral resection of the bladder tumor; (2) advancements in risk stratification tools for NMIBC; and (3) advancements in treatment strategies for BCG-treated NMIBC. Repeat transurethral resection, en-bloc transurethral resection, and enhanced tumor visualization, including photodynamic diagnosis and narrow-band imaging, help reduce residual cancer cells, provide accurate diagnosis and staging, and sensitive detection, which are the first essential steps for cancer cure. Risk stratification should always be updated and improved because the treatment strategy changes over time. The BCG-treated disease concept has recently diversified to include BCG failure, resistance, refractory, unresponsiveness, exposure, and intolerance. A BCG-unresponsive disease is an extremely aggressive subset unlikely to respond to a rechallenge with BCG. Numerous ongoing clinical trials aim to develop a future bladder-sparing approach for very high-risk BCG-naïve NMIBC and BCG-unresponsive NMIBC. The key to improving the quality of patient care lies in the continuous efforts to overcome the clinical limitations of bedside management.

Prognostication in Japanese patients with Bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer undergoing early radical cystectomy

OBJECTIVES

The US Food and Drug Administration recently defined the clinical term "Bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer" as a disease state resistant to adequate Bacillus Calmette-Guérin therapy. There is a significant lack of prognostication for this disease even in patients who have undergone early radical cystectomy. This study aimed to identify the clinical outcomes and prognostic factors in Japanese patients with Bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer who underwent early radical cystectomy.

METHODS

Data from a large-scale multicenter retrospective study included 2879 patients with highest-risk or high-risk non-muscle-invasive bladder cancer who received intravesical Bacillus Calmette-Guérin induction therapy between January 2000 and December 2019. A total of 141 patients (4.3%) met the criteria for Bacillus Calmette-Guérin-unresponsive disease, of whom 47 (33.3%) underwent early radical cystectomy. Prognostic factors for three clinical endpoints, namely, unresectable lesion-free survival, cancer-specific survival, and overall survival, were identified.

RESULTS

The highest-risk status at induction Bacillus Calmette-Guérin was associated with short unresectable lesion-free survival (hazard ratio 7.85; P < 0.05), cancer-specific survival (hazard ratio 12.24; P < 0.05), and overall survival (hazard ratio 9.25; P < 0.01). Moreover, extravesical tumors (pathological T3 or T4) on the radical cystectomy specimens were associated with poor prognosis and were found at a higher rate in patients with the highest-risk status at induction Bacillus Calmette-Guérin than in those with high-risk status (35.7% vs 21.2%).

CONCLUSIONS

The highest-risk status among the pre-Bacillus Calmette-Guérin factors was associated with upstaging to extravesical tumors and poor prognosis despite early radical cystectomy procedures. Appropriate decision-making and the correct timing of radical cystectomy are vital to avoid treatment delays and improve outcomes.

Intravesical Bacillus Calmette-Guérin Treatment for T1 High-Grade Non-Muscle Invasive Bladder Cancer with Divergent Differentiation or Variant Morphologies

The 2016 World Health Organization classification newly described infiltrating urothelial carcinoma (UC) with divergent differentiation (DD) or variant morphologies (VMs). Data comparing oncological outcomes after bladder-preservation therapy using intravesical Bacillus Calmette-Guérin (BCG) treatment among T1 bladder pure UC (pUC), UC with DD (UC-DD), and UC with VMs (UC-VM) are limited. We evaluated 1490 patients with T1 high-grade bladder UC who received intravesical BCG during 2000-2019. They were classified into three groups: 93.6% with pUC, 4.4% with UC-DD, and 2.0% with UC-VM. Recurrence-free, progression-free, and cancer-specific survival following intravesical BCG were compared among the groups using multivariate Cox regression analysis, also used to estimate inverse probability of treatment weighting-adjusted hazard ratio and 95% confidence interval for the outcomes. Glandular differentiation and micropapillary variant were the most common forms in the UC-DD and UC-VM groups, respectively. Of 1490 patients, 31% and 13% experienced recurrence and progression, respectively, and 5.0% died of bladder cancer. Survival analyses revealed the impact of concomitant VMs was significant for cancer-specific survival, but not recurrence-free and progression-free survival compared with that of pUC. Our analysis clearly demonstrated that concomitant VMs were associated with aggressive behavior in contrast to concomitant DD in patients treated with intravesical BCG.