Role of Neoadjuvant Chemotherapy in Squamous Variant Histology in Urothelial Bladder Cancer: Does Presence and Percentage Matter?

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.

Neoadjuvant therapy for muscle-invasive bladder cancer: Current clinical scenario, future perspectives, and unsolved questions

Cisplatin-based neoadjuvant chemotherapy (NAC) followed by radical cystectomy is the standard treatment for patients with muscle-invasive bladder cancer (MIBC). However, the implementation of NAC is lower than desirable mainly due to its limited impact on overall survival, patients' comorbidities and the lack of predictive biomarkers to select those patients most likely to benefit from NAC. In the last decade, improved molecular MIBC characterisation, the identification of potential predictive and prognostic biomarkers as well as the incorporation of new effective therapies with a better toxicity profile, such as immunotherapy, has changed the treatment paradigm for MIBC. Therefore, the main goal for the near future is to introduce these clinical and translational advances into routine clinical practice to personalise treatment for each patient and increase the opportunity to implement bladder preservation strategies. The present review focuses on the current status of NAC in MIBC, unsolved questions and future therapeutic approaches.

Neoadjuvant and Adjuvant Chemotherapy for Variant Histology Bladder Cancers: A Systematic Review and Meta-Analysis

Context

To improve the prognosis of variant histology (VH) bladder cancers, clinicians have used neoadjuvant chemotherapy (NAC) or adjuvant chemotherapy (AC) on the basis of radical cystectomy (RC). Despite some new data, the evidence remains mixed on their efficacy.

Objective

To update the current evidence on the role of NAC and AC for VH bladder cancers.

Evidence Acquisition

We searched for all studies investigating NAC or AC for bladder cancer patients with variant histology in PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to December 2021. The primary end points were recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS).

Evidence Synthesis

We identified 18 reports comprising a total of 10,192 patients in the NAC studies. In patients with VH, the use of NAC did improve CSS (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.55–0.99, p = 0.044), and OS (HR 0.74, 95% CI 0.66–0.84, p = 0.000), but not RFS (HR 1.15, 95% CI 0.56–2.33, p = 0.706). Subgroup analyses demonstrated that receiving NAC was associated with better OS in sarcomatoid VH (HR 0.67, 95% CI 0.54–0.83, p = 0.000) and neuroendocrine VH (HR 0.54, 95% CI 0.43–0.68, p = 0.000). For AC, we identified eight reports comprising a total of 3254 patients. There was a benefit in CSS (HR 0.61, 95% CI 0.43–0.87, p = 0.006) and OS (HR 0.76, 95% CI 0.60–0.98, p = 0.032). Subgroup analyses demonstrated that only neuroendocrine VH had better CSS (HR 0.29, 95% CI 0.13–0.67, p = 0.174) when receiving AC.

Conclusions

NAC or AC for VH bladder cancers confers an OS and CSS benefit compared with RC alone. For NAC, the benefit was independently observed in the sarcomatoid and neuroendocrine subgroups. As for AC, only neuroendocrine subgroups improved CSS.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021289487.

Overview of histologic variants of urothelial carcinoma: current trends and narrative review on treatment outcomes

Background and Objective

The histologic variants of urothelial carcinoma (UC) are tumors arising from within the urothelium in which some component of the tumor morphology is other than urothelial. They are underdiagnosed, aggressive and have varying pathologic response rates to systemic chemotherapy. There are no consensus guidelines on the use of systemic chemotherapy in variant histology (VH) of UC. We performed a contemporary review on pathologic response rates to neoadjuvant systemic therapy and survival outcomes following radical cystectomy in order to provide a rationale for clinical practice recommendations on the management of UC with VH.

Methods

A PubMed literature search was conducted for all English articles from inception reporting either pathological response rates to neoadjuvant treatment or survival outcomes after radical cystectomy in non-metastatic VH of UC.

Key Content and Findings

Neoadjuvant chemotherapy (NAC) prior to radical cystectomy was shown to be a beneficial treatment strategy in UC with VH. The micropapillary, plasmacytoid, nested and sarcomatoid histologic variants were associated with worse survival outcomes compared to conventional UC and UC with squamous or glandular differentiation despite initial downstaging with chemotherapy. There is evidence of improved survival in patients with sarcomatoid differentiation receiving NAC compared to RC alone. The major prognostic factors that affect survival outcomes in VH of UC include histologic variant subtype, patient age, presence of lymphovascular invasion, hydronephrosis, nodal metastasis and advanced T stage at diagnosis. Recent studies demonstrate that VH of UC are heterogenous tumors and responsiveness to NAC may be a function of the molecular subtypes present.

Conclusions

Based on these findings, NAC to achieve pathologic downstaging prior to radical cystectomy is recommended for MIBC with VH. Biomarkers identified by molecular profiling with immunohistochemistry will need to be validated as predictors of response to NAC in future trials.

Oncologic Outcomes of Squamous Cell Carcinoma Versus Urothelial Carcinoma With Squamous Differentiation After Radical Cystectomy for Bladder Carcinoma

INTRODUCTION

In this study we aim to compare clinicopathological characteristics and cancer specific survival between patients treated with radical cystectomy for pure squamous cell carcinoma (SCC) and urothelial carcinoma with squamous differentiation (SqD).

PATIENTS AND METHODS

We reviewed data of 1737 consecutive patients treated with radical cystectomy and urinary diversion between January 2004 and February 2014. Only patients with pure SCC or SqD were included in the analysis. Squamous differentiation was defined as intercellular bridges or keratinization in the tumor. Clinicopathological data and recurrence free survival (RFS) were compared between patients diagnosed with SCC and SqD.

RESULTS

SCC and SqD were found in 318 and 223 patients, respectively. Mean age was 57 ± 8.3 years in SCC and 58.8 ± 7.8 in SqD (P = .008). A higher proportion of female patients was observed in SCC group compared to SqD (31.8% vs. 22% P < .0001). Patients with SqD were more likely to have extravesical (58.3% vs. 46.2%: P = .006) and nodal positive disease (34.5% vs. 14.5%: P < .0001) than pure SCC patients. Bilharzial eggs were found in 61% of SCC vs. 46% of SqD (P = .001).; The median (IQR) follow up period for SCC and SqD was 63 (12-112) months and 23 months (9-74.7), respectively. The 5-year RFS for SCC and SqD were 77% and 59.8 %, respectively (P < .0001).; Multivariate cox regression analysis identified advanced pT stage (OR: 1.9, 95% CI: 1.3-2.86, P = .0001), nodal positive disease (OR: 1.6, 95% CI: 1.1-2.48, P = .01) and SqD histology (OR: 1.6, 95% CI: 1.14-2.31, P = .007 as independent predictors of 5-year RFS.

CONCLUSION

Patient with SCC had significantly higher 5-year RFS in comparison to SqD. The higher rate of extravesical disease and lymph node metastasis in SqD patients is indicative of aggressive behavior of this histologic type.