Response to Neoadjuvant Chemotherapy and Survival in Micropapillary Urothelial Carcinoma: Data From a Tertiary Referral Center and the Surveillance, Epidemiology, and End Results (SEER) Program

Clinical Outcomes of Micropapillary Urothelial Carcinoma of the Bladder Treated With Radical Cystectomy

Background/Aim

This study examined the treatment outcomes of radical cystectomy (RC) for micropapillary subtype (MPS) bladder cancer treated at our hospital.

Patients and Methods

Histopathological findings of RC specimens collected from 2003 to 2020 were evaluated. Recurrence-free survival (RFS) and overall survival (OS) after RC, as well as the efficacy of chemotherapy in cases of recurrence, were retrospectively assessed.

Results

Of 202 patients who underwent RC, seven (3.4%) had MPS bladder cancer. All seven patients underwent immediate RC without neoadjuvant chemotherapy. The median patient age was 58 years (range=52-71 years), and all patients were male. After RC, median RFS was 14 months (range=6-115 months), and median OS was 31 months (range=18-115 months). The clinical tumor stage was cT1 or lower in two patients (28.5%), cT2 in two patients (28.5%), and cT3 or higher in three patients (42.8%). No preoperative lymph node metastasis was observed. The pathological tumor stage was pT1 or lower in one patient (14.2%), pT2 in one patient (14.2%), and pT3 or higher in five patients (71.4%). The pathological lymph node stage was observed in five patients (71.4%). Although six of seven patients (85.7%) received adjuvant chemotherapy, all patients experienced relapse. The objective response rates of primary and secondary chemotherapy at relapse were both 33%. One patient received immune checkpoint inhibitor therapy and maintained stable disease for 12 months.

Conclusion

The recurrence rate after RC for MPS bladder cancer was high, and prognosis was poor.

Does Bladder Cancer Subtype Influence Pathologic Complete Response (pCR) and Pelvic Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) Response Evaluation After Neoadjuvant Chemotherapy? Pathological Perspective

INTRODUCTION

We aimed to provide a pathological perspective on the management of muscle-invasive bladder cancer (MIBC) by correlating the prechemotherapy transurethral resection of bladder tumor findings and postchemotherapy radiologic evaluation with final radical cystectomy (RC) findings.

MATERIALS AND METHODS

This retrospective study included 79 MIBC patients treated with neoadjuvant chemotherapy (NAC) and RC. Pelvic diffusion-weighted magnetic resonance imaging (DW-MRI) and pathologic reports were retrieved from our institutional database. All pathology slides were reviewed based on diagnostic criteria with high interobserver reproducibility.

RESULTS

Pathologic complete response (pCR) was confirmed in 32 patients (40.5%). The concordance and discordance between MRI and RC findings occurred in 68.3% and 31.7% of cases, respectively. The 21.5% of cases that were clinical CR (cCR) on MRI actually achieved pCR on RC specimens and 46.8% of cases that were non-cCR on MRI were actually non-pCR on RC specimens. In 19.0% of cases, RC findings were pCR, but MRI demonstrated residual tumor and the opposite was 12.7%. The greatest discrepancy between the 2 methods (75%, 3/4) was for the plasmacytoid subtype. Plasmacytoid histology was the most common histological subtype identified in RC specimens after NAC, followed by micropapillary and squamous histologies.

CONCLUSIONS

We found that all cases with plasmacytoid and micropapillary subtypes, and squamous differentiation did not show pCR. In particular, the largest discrepancy between MRI findings and RC pathology after NAC was seen in the plasmacytoid subtype. An accurate pathologic diagnosis based on strict criteria to identify histological subtypes of MIBC is necessary for proper treatment.

Characterizing the Genomic Landscape of the Micropapillary Subtype of Urothelial Carcinoma of the Bladder Harboring Activating Extracellular Mutations of ERBB2

The micropapillary subtype of urothelial carcinoma (MPUC) of the bladder is a very aggressive histological variant of urothelial bladder cancer (UBC). A high frequency of MPUC contains activating mutations in the extracellular domain (ECD) of ERBB2. We sought to further characterize ERBB2 ECD-mutated MPUC to identify additional genomic alterations that have been associated with tumor progression and therapeutic response. In total, 5,485 cases of archived formalin-fixed, paraffin-embedded UBC underwent comprehensive genomic profiling to identify ERBB2 ECD-mutated MPUC and evaluate the frequencies of genomic co-alterations. We identified 219 cases of UBC with ERBB2 ECD mutations (74% S310F and 26% S310Y), of which 63 (28.8%) were MPUC. Genomic analysis revealed that TERT, TP53, and ARID1A were the most common co-altered genes in ERBB2-mutant MPUC (82.5%, 58.7%, and 39.7%, respectively) and did not differ from ERBB2-mutant non-MPUC (86.5%, 51.9%, and 35.3%). The main differences between ERBB2 ECD-mutated MPUC compared with non-MPUC were KMT2D, RB1, and MTAP alterations. KMT2D and RB1 are tumor-suppressor genes. KMT2D frequency was significantly decreased in ERBB2 ECD-mutated MPUC (6.3%) in contrast to non-MPUC (27.6%; P < .001). RB1 mutations were more frequent in ERBB2 ECD-mutated MPUC (33.3%) than in non-MPUC (17.3%; P = .012). Finally, MTAP loss, an emerging biomarker for new synthetic lethality-based anticancer drugs, was less frequent in ERBB2 ECD-mutated MPUC (11.1%) than in non-MPUC (26.9%; P = .018). Characterizing the genomic landscape of MPUC may not only improve our fundamental knowledge about this aggressive morphological variant of UBC but also has the potential to identify possible prognostic and predictive biomarkers that may drive tumor progression and dictate treatment response to therapeutic approaches.

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.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 2: Grading of Mixed Grade, Invasive Urothelial Carcinoma Including Histologic Subtypes and Divergent Differentiations, and Non-Urothelial Carcinomas

The 2022 International Society of Urological Pathology (ISUP) Consensus Conference on Urinary Bladder Cancer Working Group 2 was tasked to provide evidence-based proposals on the applications of grading in noninvasive urothelial carcinoma with mixed grades, invasive urothelial carcinoma including subtypes (variants) and divergent differentiations, and in pure non-urothelial carcinomas. Studies suggested that predominantly low-grade noninvasive papillary urothelial carcinoma with focal high-grade component has intermediate outcome between low- and high-grade tumors. However, no consensus was reached on how to define a focal high-grade component. By 2004 WHO grading, the vast majority of lamina propria-invasive (T1) urothelial carcinomas are high-grade, and the rare invasive low-grade tumors show only limited superficial invasion. While by 1973 WHO grading, the vast majority of T1 urothelial carcinomas are G2 and G3 and show significant differences in outcome based on tumor grade. No consensus was reached if T1 tumors should be graded either by the 2004 WHO system or by the 1973 WHO system. Because of the concern for underdiagnosis and underreporting with potential undertreatment, participants unanimously recommended that the presence of urothelial carcinoma subtypes and divergent differentiations should be reported. There was consensus that the extent of these subtypes and divergent differentiations should also be documented in biopsy, transurethral resection, and cystectomy specimens. Any distinct subtype and divergent differentiation should be diagnosed without a threshold cutoff, and each type should be enumerated in tumors with combined morphologies. The participants agreed that all subtypes and divergent differentiations should be considered high-grade according to the 2004 WHO grading system. However, participants strongly acknowledged that subtypes and divergent differentiations should not be considered as a homogenous group in terms of behavior. Thus, future studies should focus on individual subtypes and divergent differentiations rather than lumping these different entities into a single clinicopathological group. Likewise, clinical recommendations should pay attention to the potential heterogeneity of subtypes and divergent differentiations in terms of behavior and response to therapy. There was consensus that invasive pure squamous cell carcinoma and pure adenocarcinoma of the bladder should be graded according to the degree of differentiation. In conclusion, this summary of the International Society of Urological Pathology Working Group 2 proceedings addresses some of the issues on grading beyond its traditional application, including for papillary urothelial carcinomas with mixed grades and with invasive components. Reporting of subtypes and divergent differentiation is also addressed in detail, acknowledging their role in risk stratification. This report could serve as a guide for best practices and may advise future research and proposals on the prognostication of these tumors.

The prognostic significance of histologic variant on survival outcomes in patients with metastatic urothelial carcinoma receiving immune checkpoint inhibitor therapy

BACKGROUND

While the treatment guidelines have been established for pure urothelial carcinoma (pUC), patients with variant type urothelial carcinoma (vUC) face limited effective treatment options. The effectiveness of immune checkpoint inhibitors (ICI) in patients with vUC remains uncertain and necessitates additional research.

METHOD

We conducted a retrospective, multicenter study to explore the effectiveness of ICI in patients with pUC or vUC in Taiwan. We evaluated the overall response rate (ORR) through univariate logistic regression analysis and examined the overall survival (OS) and progression-free survival (PFS) using Kaplan-Meier analysis. Additionally, we employed univariate and multivariate Cox proportional hazards models to analyze the data.

RESULT

A total of 142 patients (116 pUC, 26 vUC) were included in our final analysis. The ORR was marginally higher in patients with pUC compared to those with vUC (34.5% vs. 23.1%, p = 0.26). Among all patients, 12.9% with pUC achieved a complete response (CR) after ICI treatment, while no vUC cases achieved CR (p = 0.05). There were no significant differences in PFS (median 3.6 months vs. 4.1 months, p = 0.34) or OS (median 16.3 months vs. 11.0 months, p = 0.24) when comparing patients with pUC or vUC. In the subgroup analysis, patients with pUC who underwent first-line ICI treatment exhibited significantly improved OS compared to those with vUC (24.6 months vs. 9.1 months, p = 0.004).

CONCLUSION

The use of ICI as monotherapy is a feasible and effective treatment approach for patients with metastatic vUC.

Oncologic outcomes of neoadjuvant chemotherapy in patients with micropapillary variant urothelial carcinoma of the bladder

BACKGROUND

There is lack of consensus about the effectiveness of neoadjuvant platinum-based chemotherapy in patients with micropapillary variant urothelial carcinoma (MVUC) prior to radical cystectomy. We studied the association between neoadjuvant chemotherapy (NAC) and pathologic response (PR) among patients with micropapillary versus non-variant bladder urothelial carcinoma (UC).

METHODS

We queried the National Cancer Database to identify patients with localized UC and MVUC from 2004 to 2017. We restricted our analysis to patients who underwent radical cystectomy with or without NAC. We compared clinical, demographic, and pathologic characteristics associated with NAC. We used multivariable logistic regression and propensity score matching to examine the association between NAC and the occurrence of a pathologic complete response (pT0) and pathologic lymph node positivity (pN+). Kaplan Meier analyses and Cox proportional hazards models were used to assess overall survival (OS). We performed analyses among subsets of patients with clinical stage II (cT2) disease, as well as the entire cohort (cT2-T4).

RESULTS

We identified 18,761 patients, including 18,027 with non-variant UC and 734 patients with MVUC. Multivariable analysis revealed that NAC use was associated with greater odds of pT0 (9.64[7.62-12.82], P<0.001), and the association did not differ significantly between MVUC and non-variant UC. In a propensity matched analysis of patients with MVUC, NAC use was associated with higher odds of pT0 (OR 4.93 [2.43-13.18] P<0.001), lower odds of pN+ (OR 0.52 [0.26-0.92] P=0.047) and pathologic upstaging (OR 0.63 [0.34-0.97] P=0.042) in all stages. Similar findings were observed with cT2 disease. No significant association was seen between NAC and OS with MVUC (HR 0.89 [0.46-1.10] P=0.63), including the subset of patients with cT2 (HR 0.83 [0.49-1.06] P=0.58).

CONCLUSIONS

NAC is associated with similar pathologic and nodal responses in patients with localized MVUC and non-variant UC. Improvements in pathologic findings did not translate into OS in this retrospective hospital-based registry study.

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.

Micropapillary bladder cancer: an evolving biology

PURPOSE OF REVIEW

To summarize a comprehensive overview of more recent evidence on micropapillary bladder cancer (MPBC), focusing on actual incidence, clinical features, therapeutic strategies, and prognosis.

RECENT FINDINGS

MPBC generally exhibits an aggressive behaviour compared with pure urothelial carcinoma (pUC) with advances in tumour stage and nodal and distant spread at diagnosis. Due to its rarity and presence of only small sample size and retrospective studies, no consensus currently exists regarding the most effective therapeutic strategy to be performed among nonmuscle-invasive (conservative treatment versus immediate radical cystectomy) and muscle-invasive MPBC (neoadjuvant therapy versus upfront radical cystectomy versus adjuvant chemotherapy).

SUMMARY

The incidence of MPBC is recently increased according to latter literature, ranging from 2.9 to 7.6% of all bladder cancer. Despite its aggressive behaviour at time of presentation, more recent evidence fails to demonstrate a significant association between MPBC and worse outcomes compared with pUC when adjusted for clinical and pathological features. According to latter evidence, MPBC pathological response to NAC appears to be unsatisfactory compared with pUC patients while neoadjuvant immunotherapy with Pembrolizumab may represent an effective treatment among MPBC patients, based on PD-L1 and TMB expression.

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.

Micropapillary bladder cancer: an added indication to prophylactic urethrectomy

There is little research on the role of urethrectomy during cystectomy in patients with micropapillary bladder cancer (MPBC). We present two cases of MPBC cystectomy and suggest that urethrectomy be performed concurrently as a preventive measure. The first case involved a woman who had a mixed solid and papillary bladder tumour. An anterior pelvic exenteration was performed as well as a total urethrectomy. The T4a micropapillary variant tumour was confirmed by pathology. The second case involved a man with T1 MPBC who was treated with a BCG induction course. A recurrent muscle-invasive MPBC was discovered during follow-up. During the radical cystoprostatectomy, the urethra was spared. T2 MPBC was discovered through pathology. He had a urethrectomy 6 months later due to urethral bleeding, and the pathology revealed micropapillary cancer of the urethra.