Bladder preserving chemoradiotherapy compared to surgery for variants of urothelial carcinoma and other tumors types involving the bladder: An analysis of the National Cancer Database

One Size Fits Some: Approaching Rare Malignancies of the Urinary Tract

OPINION STATEMENT

Urothelial carcinoma is the predominant cancer of the urinary tract but when divergent and subtype histology (non-urothelial) are identified at time of pathologic diagnosis, therapeutic and diagnostic challenges transpire. To this end, pathologic review to confirm any non-urothelial histology is key since these subtypes can often be overlooked. Few prospective trials are dedicated to understanding these non-urothelial histologic types; however, current, and past trials did allow patients with these non-urothelial histologic types to enroll, and inferences can be made about treatment efficacy and survival. Existing treatment regimens for non-urothelial bladder cancers are akin to standard urothelial cancer regimens using surgical approaches for localized disease and platinum-based chemotherapy for advanced disease. The reported clinical trials, that will be discussed, center on non-urothelial histologic types. These studies, albeit limited, provide critical insight into tumor biology and response to standard platinum-based chemotherapy, immune checkpoint inhibitors, and antibody drug conjugates. The inclusion of non-urothelial histologic types will be essential for clinical trials in development to provide further therapeutic advances and provide essential efficacy data.

Comparative survival analysis of bladder preservation therapy versus radical cystectomy in muscle-invasive bladder cancer

BACKGROUND

Bladder preservation therapy is an alternative to radical cystectomy in patients with muscle-invasive bladder cancer (MIBC). The purpose of this study is to compare survival outcomes between bladder preservation therapy and radical cystectomy in MIBC patients using an Asian nationwide cancer registry database.

METHODS

From the Taiwan Cancer Registry database and the Taiwan National Health Insurance Research Database, we identified bladder cancer patients from 2008 to 2018. The patients with urothelial carcinoma and clinical stage T2-T4aN0-1 M0 were included. Propensity score matching by age, gender, clinical stage, cT classification, and Charlson Comorbidity Index score was used between those receiving bladder preservation therapy or radical cystectomy. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were compared using the Kaplan-Meier method. Multivariate Cox regression models were used to determine the predictive factors of OS, CSS, and DFS.

RESULTS

Following the propensity score matching, 393 MIBC patients were analyzed, 131 (33.3%) receiving bladder preservation therapy and 262 (66.7%) receiving radical cystectomy. After 5 years of the follow-up period the overall duration was with a median of 15.6 months. The treatment groups did not differ significantly in OS, CSS, and DFS (p = 0.2681, 0.7208, and 0.3616, respectively). In multivariable Cox regression models, bladder preservation therapy remained non-inferior to radical cystectomy in OS (adjusted hazard ratio [aHR] 1.08; 95% confidence interval [CI], 0.77-1.50; p = 0.6689), CSS (aHR, 1.06; 95% CI, 0.72-1.57; p = 0.7728), and DFS (aHR, 0.76; 95% CI, 0.46-1.27; p = 0.2929). Additionally, among patients ≥80 years, the use of bladder preservation therapy compared with radical cystectomy resulted in an equivalent OS, CSS and DSS.

CONCLUSION

In Asian populations, bladder preservation therapy yielded similar survival outcomes as radical cystectomy in MIBC patients. Based on the results, it is evident that a multidisciplinary approach and shared decision-making are recommended for bladder cancer treatment.

Bladder cancer: therapeutic challenges and role of 3D cell culture systems in the screening of novel cancer therapeutics

Bladder cancer (BC) is the sixth most common worldwide urologic malignancy associated with elevated morbidity and mortality rates if not well treated. The muscle-invasive form of BC develops in about 25% of patients. Moreover, according to estimates, 50% of patients with invasive BC experience fatal metastatic relapses. Currently, resistance to drug-based therapy is the major tumble to BC treatment. The three-dimensional (3D) cell cultures are clearly more relevant not only as a novel evolving gadget in drug screening but also as a bearable therapeutic for different diseases. In this review, various subtypes of BC and mechanisms of drug resistance to the commonly used anticancer therapies are discussed. We also summarize the key lineaments of the latest cell-based assays utilizing 3D cell culture systems and their impact on understanding the pathophysiology of BC. Such knowledge could ultimately help to address the most efficient BC treatment.

Partial cystectomy for bladder squamous cell carcinoma with a 10-year follow-up: a case report

Squamous cell carcinoma (SCC) of the bladder is a rare malignancy of the urinary system. It is prone to invasion and metastasis in the early stage and has a poor prognosis. This case reports a 65-year-old female patient with SCC of the bladder who was free of disease recurrence and metastasis 10 years after partial cystectomy (PC) combined with left ureteral reimplantation. The treatment plan and admission of this patient were retrospectively analyzed in order to provide some reference significance for the treatment plan for the SCC of the bladder.

Challenges and opportunities in the management of non-urothelial bladder cancers

Urothelial carcinoma accounts for approximately 90% of all bladder cancer diagnoses. Localized, muscle-invasive disease is often managed with a multidisciplinary approach including either neoadjuvant chemotherapy (NAC) followed by radical cystectomy or concurrent chemoradiation, whereas multiple immunotherapies and novel antibody drug conjugates have recently joined platinum-based chemotherapy as standard of care therapy for metastatic disease. However, the clinical trials leading to these standards often require majority if not complete urothelial histology for eligibility. As many as one quarter of patients diagnosed with bladder cancer will have either divergent differentiation of their urothelial carcinoma or an alternate epithelial tumor such as squamous cell carcinoma, adenocarcinoma, or small cell carcinoma; even more rare are non-epithelial tumors such as sarcoma. The rarity of these diseases and their general exclusion from treatment within prospective clinical trials has created a challenging situation where treatment plans are often derived from case series or extrapolated from other disease types and outcomes are poor compared to pure urothelial carcinoma. In this review, we summarize the existing data on the diagnosis and treatment of epithelial, non-urothelial bladder cancers including adenocarcinoma, squamous cell carcinoma, and small cell carcinoma in their localized and advances stages. We will also review the current clinical trial landscape investigating novel approaches to these diseases.

Bladder Preservation for Muscle-Invasive Bladder Cancer With Variant Histology

A growing body of evidence has shown bladder-preservation with chemo-radiotherapy achieves comparable survival to Radical Cystectomy (5-year OS 50%-70%) and superior quality of life outcomes for patients with muscle-invasive urothelial carcinoma of the bladder (UC). However, up to 55% of patients harbor variant histology and in this review we aim to clarify the role of bladder-preservation for this group. We first draw the distinction between urothelial carcinoma with divergent differentiation (UCDD) and non-urothelial carcinoma (NUC). UCDD is common, increasing in prevalence, and whilst each subtype may have its own characteristics current evidence suggests comparable outcomes with radical cystectomy and bladder-preservation. Non-urothelial carcinoma is a collection of distinct pathologies each deserving of its own management strategy. However, these tumors are rare, and evidence is generated from retrospective studies with significant inherent bias. Small cell carcinoma of the bladder has good evidence for bladder-preservation; however, other pathologies such as Squamous Cell Carcinoma and Adenocarcinoma are not well supported. We recommend careful multidisciplinary appraisal of the evidence for each subtype and honest patient discussion about the limited evidence before reaching management decisions. As we look to the future molecular-profiling may help better characterize these tumors and aid in treatment selection.

Differences in Cancer-Specific Mortality after Trimodal Therapy for T2N0M0 Bladder Cancer according to Histological Subtype

We aimed at assessing the impact of non-urothelial variant histology (VH), relative to urothelial carcinoma of the urinary bladder (UCUB), on cancer-specific mortality (CSM) in T2N0M0 bladder cancer patients treated with trimodal therapy (TMT). TMT patients treated for T2N0M0 bladder cancer were identified within the Surveillance, Epidemiology, and End Results database (2000−2018). Patients who underwent TMT received trans-urethral resection of the bladder tumor, chemotherapy, and radiotherapy. CSM-FS rates were tested using Kaplan−Meier plots and multivariable Cox-regression (MCR) models according to histological subtype: UCUB vs. neuroendocrine carcinoma vs. squamous cell carcinoma vs. adenocarcinoma. A total of 3846 T2N0MO bladder cancer patients treated with TMT were identified. Of these, 3627 (94.3%) harbored UCUB, while 105 (2.7%), 85 (2.2%), and 29 (0.8%) harbored neuroendocrine carcinoma, squamous cell carcinoma, and adenocarcinoma, respectively. In Kaplan−Meier analyses, 3-yr CSM-FS rates were 57% for UCUB, 51% for neuroendocrine carcinoma, 35% for squamous cell carcinoma, and 60% for adenocarcinoma (p-value < 0.0001). In MCR models, only squamous cell carcinoma exhibited higher CSM than UCUB (HR 1.98, 95%CI 1.5−2.61, p-value < 0.001). Despite the small number of observations, squamous cell carcinoma distinguished itself from UCUB based on worse survival in T2N0M0 patients after TMT.