Sarcomatoid variant urothelial carcinoma of the bladder: a systematic review and meta-analysis of the clinicopathological features and survival outcomes

Current Advances in the Management of Nonurothelial Subtypes of Bladder Cancer

Urothelial cancer (UC) is the most common histology seen in bladder tumors. The 2022 WHO classification of urinary tract tumors includes a list of less common subtypes (formerly known as variants) for invasive UC which are considered high-grade tumors. This review summarizes the most recent advances in the management of selected nonurothelial subtypes of bladder cancer: squamous cell carcinoma, small cell carcinoma, sarcomatoid urothelial carcinoma, micropapillary carcinoma, plasmacytoid carcinoma, adenocarcinoma, and urachal carcinoma. The role of neoadjuvant and adjuvant chemotherapy has not been well characterized for most of these histologies, and prospective data are extremely limited. Participation in clinical trials is recommended in advanced disease.

Metastatic Urothelial Carcinoma With Sarcomatoid Subtype After Robot-Assisted Radical Cystectomy Successfully Treated With Pembrolizumab

A 76-year-old man who was diagnosed with urothelial carcinoma (UC) in the bladder diverticulum was referred to our institution. The patient was diagnosed with muscle-invasive bladder cancer, which was confirmed by magnetic resonance imaging that showed tumor invasion into the fatty tissue surrounding the diverticulum. After two cycles of neoadjuvant gemcitabine and cisplatin, he underwent robot-assisted radical cystectomy (RARC) with pelvic lymph node dissection followed by intracorporeal ileal conduit. The histopathologic diagnosis of the bladder tumor was UC with squamous differentiation and sarcomatoid subtype and ypT3bN0M0 without positive surgical margins. The patient refused any adjuvant therapy. Six months after RARC, the patient visited our institution with a complaint of suddenly occurring generalized pain. Because 18F-fluorodeoxyglucose positron emission tomography-CT showed multiple metastases, including bone, para-aortic lymph nodes, and pleura, pembrolizumab was initiated as a second-line treatment. After two courses of pembrolizumab, the patient's symptoms remarkably improved, and the abnormal systemic accumulation on PET-CT almost disappeared. After 26 months of continuous treatment with pembrolizumab, the patient remains disease-free. Several studies have been reported that focused on tumor subtypes and programmed cell death ligand 1 (PD-L1)-positive tumor cells as candidate biomarkers in relation to the efficacy of pembrolizumab. The higher proportion of PD-L1-positive cells in the sarcomatoid subtype may have resulted in favorable oncological outcomes compared with pure UC.

Clofarabine Has a Superior Therapeutic Window as compared to Gemcitabine in Preclinical Bladder Cancer Models

Current standard-of-care systemic therapy options for locally advanced and metastatic bladder cancer (BC), which are predominantly based on cisplatin-gemcitabine combinations, are limited by significant treatment failure rates and frailty-based patient ineligibility. We previously addressed the urgent clinical need for better-tolerated BC therapeutic strategies using a drug screening approach, which identified outstanding antineoplastic activity of clofarabine in preclinical models of BC. To further assess clofarabine as a potential BC therapy component, we conducted head-to-head comparisons of responses to clofarabine versus gemcitabine in preclinical in vitro and in vivo models of BC, complemented by in silico analyses. In vitro data suggest a distinct correlation between the two antimetabolites, with higher cytotoxicity of gemcitabine, especially against several nonmalignant cell types, including keratinocytes and endothelial cells. Accordingly, tolerance of clofarabine (oral or intraperitoneal application) was distinctly better than for gemcitabine (intraperitoneal) in patient-derived xenograft models of BC. Clofarabine also exhibited distinctly superior anticancer efficacy, even at dosing regimens optimized for gemcitabine. Neither complete remission nor cure, both of which were observed with clofarabine, were achieved with any tolerable gemcitabine regimen. Taken together, our findings demonstrate that clofarabine has a better therapeutic window than gemcitabine, further emphasizing its potential as a candidate for drug repurposing in BC. PATIENT SUMMARY: We compared the anticancer activity of clofarabine, a drug used for treatment of leukemia but not bladder cancer, and gemcitabine, a drug currently used for chemotherapy against bladder cancer. Using cell cultures and mouse models, we found that clofarabine was better tolerated and more efficacious than gemcitabine, and even cured implanted tumors in mouse models. Our results suggest that clofarabine, alone or in combination schemes, might be superior to gemcitabine for the treatment of bladder cancer.

Bladder-Preserving Trimodality Therapy With Capecitabine

INTRODUCTION

Many patients with muscle-invasive bladder cancer are poor candidates for radical cystectomy or trimodality therapy with maximal transurethral resection of bladder tumor (TURBT) and chemoradiotherapy with cisplatin or mitomycin C. Given the benefit of chemotherapy in bladder-preserving therapy, less-intense concurrent chemotherapy regimens are needed. This study reports on efficacy and toxicity for patients treated with trimodality therapy using single-agent concurrent capecitabine.

MATERIALS AND METHODS

Patients deemed ineligible for radical cystectomy or standard chemoradiotherapy by a multidisciplinary tumor board and patients who refused cystectomy were included. Following TURBT, patients received twice-daily capecitabine (goal dose 825 mg/m2) concurrent with radiotherapy to the bladder +/- pelvis depending on nodal staging and patient risk factors. Toxicity was evaluated prospectively in weekly on-treatment visits and follow-up visits by the treating physicians. Descriptive statistics are provided. Overall, progression-free, cancer-specific, distant metastasis-free, and bladder recurrence-free survival were estimated using the Kaplan-Meier method.

RESULTS

Twenty-seven consecutive patients met criteria for inclusion from 2013 to 2023. The median age was 79 with 9 patients staged cT3-4a and 7 staged cN1-3. The rate of complete response in the bladder and pelvis was 93%. Overall, progression-free, cancer-specific, distant metastasis-free, and bladder recurrence-free survival at 2 years were estimated as 81%, 65%, 91%, 75%, and 92%, respectively. There were 2 bladder recurrences, both noninvasive. There were 7 grade 3 acute hematologic or metabolic events but no other grade 3+ toxicities.

CONCLUSION

Maximal TURBT followed by radiotherapy with concurrent capecitabine offers a high rate of bladder control and low rates of acute and late toxicity.

Impact of variant histology on upstaging and survival in patients with nonmuscle invasive bladder cancer undergoing radical cystectomy

INTRODUCTION

Variant histology (VH) of urothelial carcinoma is uncommon and frequently presents at the muscle-invasive stage. VH is considering a significant risk factor for progression among patients with nonmuscle invasive bladder cancer (NMIBC). While there is some debate, expert opinion is generally that upfront radical cystectomy (RC) should be consider for these patients. Limited data exists to support this position. In this study, we sought to examine the rate of upstaging and overall survival for patients with VH NMIBC against patients with pure urothelial NMIBC who underwent RC, to help clarify the optimal treatment strategy for these patients.

METHODS

The institutional REDCap database was utilized to identify all patients with T1 and Ta bladder cancer that underwent RC over the study period (2004-2022). Matched-pair analysis was performed between patients with VH and pure urothelial NMIBC; 42 pairs were matched on prior intravesical therapy, presence of muscularis propria on transurethral resection of bladder tumor (TURBT), any carcinoma in situ presence on prior TURBTs, and final tumor staging on TURBT. The primary outcomes of interest were pathologic tumor upstaging rate at RC and overall survival. Secondary outcomes of interest included association of demographic or pretreatment variables with upstaging, and upstaging rates for specific variant histologies.

RESULTS

Patients with VH NMIBC undergoing RC were upstaged at a significantly higher rate than a matched cohort of patients with pure urothelial NMIBC (73.8% vs. 52.4%, P = 0.0244) and among those upstaged, had significantly higher rates of pT3 to pT4 (54.7% vs. 23.8%, P = 0.0088). Rate of node positivity at RC for VH NMIBC was also higher compared to pure urothelial NMIBC (40.5% vs. 21.4%, P = 0.0389). Among histologic variants, patients with plasmacytoid and sarcomatoid subtypes demonstrated the highest rates of upstaging; differences were not statistically significant. The overall median survival was 28.4 months for patients with VH after RC compared to 155.1 months for patients with pure urothelial NMIBC (P = 0.009).

CONCLUSION

Patients with VH NMIBC undergoing RC are at significantly higher risk of upstaging at RC when compared to patients with pure urothelial NMIBC and have worse overall survival. While this study supports the concept of an aggressive treatment approach for patients with VH NMIBC, improvements in understanding of the disease are necessary to improve outcomes.

Exploring the Rare Case of a Sarcomatoid Variant of Urothelial Carcinoma

A sarcomatoid variant of urothelial carcinoma (SVUC) is an extremely rare variant, which accounts for only 0.1-0.3% of all urothelial carcinomas of the bladder. SVUC is distinguished by the presence of biphasic components; there can be morphological and/or immunohistochemical substantiation of epithelial and mesenchymal differentiation. The patients with this variant have been associated with very poor disease-specific and overall survival rates in comparison with the high-grade pure urothelial carcinoma. Being a rare entity, it usually presents at a higher grade and is related to a dismal prognosis in comparison with conventional urothelial carcinoma. Careful examination, early diagnosis, and effective treatment are the most important steps for good survival. Here, we report a 58-year-old male who presented with complaints of hematuria for one and a half months with histopathology showing features of SVUC.

Clinical efficacy analysis of partial cystectomy and radical cystectomy in the treatment of muscle-invasive sarcomatoid carcinoma of the urinary bladder

Objective

This study compares the clinical efficacy of partial cystectomy (PC) versus radical cystectomy (RC) in the treatment of muscle-invasive bladder urothelial carcinoma (SCUB) through a retrospective analysis.

Methods

We retrospectively analyzed the clinical data of 20 patients diagnosed with muscle-invasive SCUB from July 2015 to August 2023 at Ganzhou People's Hospital. All patients underwent surgical treatment followed by chemotherapy, with 9 receiving PC and 11 undergoing RC. We compared the average survival time of deceased patients for both treatments and conducted survival and multivariate analyses using the Kaplan-Meier method and Cox proportional hazards model, respectively.

Results

All 20 patients were postoperatively diagnosed with muscle-invasive SCUB and were followed up for 4 to 60 months. The average survival time for patients undergoing PC was 11.5 months, with survival rates at 1 year, 2 years, and 5 years of 55.56%, 22.22%, and 11.11%, respectively. In contrast, patients receiving RC had an extended average survival time of 22.5 months, and their 1-year, 2-year, and 5-year survival rates increased to 63.64%, 36.36%, and 18.18%, respectively. Survival analysis revealed statistically significant differences in prognosis between PC and RC for the treatment of muscle-invasive SCUB (P<0.05).

Conclusion

SCUB is a rare malignant tumor with unique biological characteristics often associated with poor prognosis. Upon diagnosis, RC should be considered as an early treatment approach when the patient's overall condition permits.

The Many Faces of Urothelial Carcinomas: An Update From Pathology to Clinical Approach and Challenges in Practice

Urothelial carcinoma is a heterogeneous disease with histomorphological and genomic variations throughout the same tumor or between tumors from different patients. It has been shown that most of these histologic and genetic differences have prognostic significance and may have a guiding role in determining the appropriate treatment choice for the patient. Therefore, it is crucial for both the pathologist and the clinician to be conscious of these variations and to consider them in patient management. Recently, a consensus molecular classification has been developed and categorized urothelial carcinomas into 6 subclasses. These molecular subclasses seem to be associated with prognosis and/or response to certain therapeutic approaches like chemotherapy or immune checkpoint inhibitory therapy; however, it has not yet been sufficiently validated and has some limitations for routine application. As is well known, there are therapeutic limitations in locally advanced or metastatic urothelial carcinomas, especially those inappropriate for standard therapy with platinum-based chemotherapy regimens. Emerging new therapeutic approaches and testing for appropriate patient selection for those are discussed in this article.

Prognostic value of the sarcomatoid component in bladder cancer: A propensity score matching study

Sarcomatoid carcinoma of the bladder is rare, and little is known about the prognostic impact of the proportion of sarcomatoid components of the bladder. The present study aimed to assess the prognostic value of the proportion of sarcomatoid components with regard to death and recurrence rates in patients with bladder cancer (BC), and to validate the worse survival results of sarcomatoid carcinomas of the bladder using propensity score matching. Patients with sarcomatoid carcinoma of the bladder who were treated at the Affiliated Hospital of Qingdao University between August 2010 and May 2021 were included in the study. A 1:2 propensity score matching system based on age, sex and pathological T stage was used for sarcomatoid and non-sarcomatoid carcinoma matching. Finally, 114 patients with BC were included. Patients with sarcomatoid carcinoma had worse 5-year cancer-specific survival (CSS) (69.1 vs. 86.9%; log-rank P=0.008) and recurrence-free survival (RFS) (64.1 vs. 83.6%; log-rank P=0.001) rates compared with patients with non-sarcomatoid carcinoma, as had the subgroup with muscle invasion. Multivariate analysis revealed sarcomatoid carcinoma as an independent prognostic factor. Patients with a low proportion of sarcomatoid components (1-50%) had a better prognosis than patients with a high proportion (>50%), and no significant difference was found compared with the non-sarcomatoid group. Overall, a proportion of sarcomatoid components >50% was a predictor of CSS and RFS. Sarcomatoid components markedly increased the risk of death and recurrence in muscle-invasive BC, but not in non-muscle-invasive BC. A higher proportion of sarcomatoid components was significantly associated with poorer survival.

Molecular and Pharmacological Bladder Cancer Therapy Screening: Discovery of Clofarabine as a Highly Active Compound

BACKGROUND

The heterogeneity of bladder cancers (BCs) is a major challenge for the development of novel therapies. However, given the high rates of recurrence and/or treatment failure, the identification of effective therapeutic strategies is an urgent clinical need.

OBJECTIVE

We aimed to establish a model system for drug identification/repurposing in order to identify novel therapies for the treatment of BC.

DESIGN, SETTING, AND PARTICIPANTS

A collection of commercially available BC cell lines (n = 32) was comprehensively characterized. A panel of 23 cell lines, representing a broad spectrum of BC, was selected to perform a high-throughput drug screen.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Positive hits were defined as compounds giving >50% inhibition in at least one BC cell line.

RESULTS AND LIMITATIONS

Amongst >1700 tested chemical compounds, a total of 471 substances exhibited antineoplastic effects. Clofarabine, an antimetabolite drug used as third-line treatment for childhood acute lymphoblastic leukaemia, was amongst the limited number of drugs with inhibitory effects on cell lines of all intrinsic subtypes. We, thus, reassessed the substance and confirmed its inhibitory effects on commercially available cell lines and patient-derived cell cultures representing various disease stages, intrinsic subtypes, and histologic variants. To verify these effects in vivo, a patient-derived cell xenograft model for urothelial carcinoma (UC) was used. Well-tolerated doses of clofarabine induced complete remission in all treated animals (n = 12) suffering from both early- and late-stage disease. We further took advantage of another patient-derived cell xenograft model originating from the rare disease entity sarcomatoid carcinoma (SaC). Similarly to UC xenograft mice, clofarabine induced subcomplete to complete tumour remissions in all treated animals (n = 8).

CONCLUSIONS

The potent effects of clofarabine in vitro and in vivo suggest that our findings may be of high clinical relevance. Clinical trials are needed to assess the value of clofarabine in improving BC patient care.

PATIENT SUMMARY

We used commercially available cell lines for the identification of novel drugs for the treatment of bladder cancer. We confirmed the effects of one of these drugs, clofarabine, in patient-derived cell lines and two different mouse models, thereby demonstrating a potential clinical relevance of this substance in bladder cancer treatment.

Sarcomatoid urothelial carcinoma arising in the female urethral diverticulum

A sarcomatoid variant of urothelial carcinoma in the female urethral diverticulum has not been reported previously. A 66-year-old woman suffering from dysuria presented with a huge urethral mass invading the urinary bladder and vagina. Histopathological examination of the resected specimen revealed predominantly undifferentiated pleomorphic sarcoma with sclerosis. Only a small portion of conventional urothelial carcinoma was identified around the urethral diverticulum, which contained glandular epithelium and villous adenoma. The patient showed rapid systemic recurrence and resistance to immune checkpoint inhibitor therapy despite high expression of programmed cell death ligand-1. We report the first case of urethral diverticular carcinoma with sarcomatoid features.