Is Immediate Radical Cystectomy Necessary for All Patients with Non-Muscle-Invasive Micropapillary Bladder Cancer?

Early experience with sequential intravesical gemcitabine and docetaxel for micropapillary variant non-muscle invasive bladder cancer

BACKGROUND

Guidelines lack clear recommendations regarding conservative management of micropapillary (MP) variant non-muscle invasive bladder cancer (NMIBC). Bladder-sparing therapy using intravesical Bacillus Calmette-Guerin (BCG) has been reported although there are concerns regarding recurrence and progression with this approach. Due to the ongoing BCG shortage, we have utilized sequential intravesical gemcitabine and docetaxel (Gem/Doce) as primary therapy for NMIBC, including some cases with limited MP urothelial carcinoma (MPUC). To compare oncologic outcomes of patients with non-muscle invasive MPUC and conventional UC treated with Gem/Doce.

METHODS

A secondary analysis of 138 patients with high-risk NMIBC treated with intravesical Gem/Doce from January 2011 to December 2021 was performed. Oncologic outcomes were compared in patients with or without MPUC using the Kaplan-Meier method.

RESULTS

Median follow-up (f/u) for all patients was 23 months (IQR 13-34). There were 129 patients with pure UC and 9 with MPUC. In those with MPUC, all were high-grade (HG), 8/9 were stage T1, 7/9 had a focal MP component (extent < 10%), 3/9 had concomitant CIS, and 2/9 had lymphovascular invasion. All MPUC tumors were re-resected, and 4 had T0, 3 had T1 HG, 1 had Ta HG, 1 had carcinoma in situ (CIS); none had residual MP or LVI tumors before Gem/Doce treatment. The 24-month high-grade recurrence-free survival was 89% and 80% in patients with MPUC and pure UC, respectively. Survival outcomes did not significantly differ between patients with and without MPUC. Four patients with MPUC experienced recurrent NMIBC after Gem/Doce, and all were treated successfully with rescue sequential intravesical valrubicin and docetaxel (Val/Doce). Pathology of these four recurrent patients revealed more aggressive histologic features in the original tumor including: multifocal tumor (3/4), T1 HG disease (4/4), concomitant CIS (2/4), and moderate MP variant extent (30%) (1/4). No patient with MPUC underwent cystectomy, experienced progression, or died at last follow-up (median f/u of 43 months).

CONCLUSIONS

Gem/Doce with Val/Doce rescue appears to have activity against carefully selected non-muscle invasive MPUC with favorable histology. Larger prospective trials are needed to validate these results.

Survival Outcomes After Immediate Radical Cystectomy Versus Conservative Management with Bacillus Calmette-Guérin Among T1 High-grade Micropapillary Bladder Cancer Patients: Results from a Multicentre Collaboration

BACKGROUND

Literature lacks clear evidence regarding the optimal treatment for non-muscle-invasive micropapillary bladder cancer (MPBC) due to its rarity and the presence of only small sample size and single-centre studies.

OBJECTIVE

To assess cancer-specific mortality (CSM) and overall mortality (OM) between immediate radical cystectomy (RC) and conservative management among T1 high-grade (HG) MPBC.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analysed a multicentre dataset including 119 T1 HG MPBC patients treated between 2005 and 2019 at 15 tertiary referral centres. The median follow-up time was 35 mo (interquartile range: 19-64).

INTERVENTION

Patients underwent immediate RC versus conservative management with bacillus Calmette-Guérin.

OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS

Cumulative incidence functions and Kaplan-Meier methods were applied to estimate survival outcomes. Multivariable Cox analyses were performed to assess independent predictors of disease recurrence and disease progression after conservative management; covariates consisted of pure MPBC, concomitant lymphovascular invasion (LVI), and carcinoma in situ at initial diagnosis.

RESULTS AND LIMITATIONS

Immediate RC and conservative management were performed in 27% and 73% of patients, respectively. CSM and OM did not differ significantly among patient treated with immediate RC versus conservative management (Pepe-Mori test p = 0.5 and log-rank test p = 0.9, respectively). Overall, 66.7% and 34.5% of patients experienced disease recurrence and disease progression after conservative management, respectively. At multivariable Cox analyses, concomitant LVI was an independent predictor of disease recurrence (p = 0.01) and progression (p = 0.03), while pure MPBC was independently associated with disease progression (p = 0.03). The absence of a centralised re-review and the retrospective design represent the main limitations of our study.

CONCLUSIONS

Conservative management could achieve satisfactory results among T1 HG MPBC patients with neither pure MPBC nor LVI at initial diagnosis.

PATIENT SUMMARY

Bacillus Calmette-Guérin seems to be an effective therapy for T1 micropapillary bladder cancer patients with neither pure micropapillary disease nor lymphovascular invasion at initial diagnosis.

Non-Muscle Invasive Bladder Cancer with Variant Histology: Biological Features and Clinical Implications

BACKGROUND

The most common bladder cancer (BC) histotype is pure urothelial carcinoma (UC), which may undergo divergent differentiation in some cases. Variant histology (VH) presents along variable morphologies, either single or combined between them or with pure UC. From a clinical standpoint, the vast majority of BC is diagnosed at non-invasive or minimally invasive stages, namely as non-muscle invasive BC (NMIBC). There is a wide range of therapeutic options for patients with NMIBC, according to their clinical and pathological features. However, current risk stratification models do not show optimal effectiveness. Evidence from the literature suggests that VH has peculiar biological features, and may be associated with poorer survival outcomes compared to pure UC.

SUMMARY

In order to describe the biological features and prognostic/predictive role of VH in NMIBC, and to discuss current treatment options, we performed a systematic literature search through multiple databases (PubMed/Medline, Google Scholar) for relevant articles according to the following terms, single and/or in combination: "non-muscle invasive bladder cancer," "variant histology," "micropapillary variant," "glandular differentiation," "squamous differentiation," "nested variant," "plasmacytoid variant," and "sarcomatoid variant." We extracted 99 studies including original articles, reviews, and systematic reviews, and subsequently analyzed data from 16 studies reporting on the outcome of NMIBC with VH. We found that the relative rarity of these forms as well as the heterogeneity in study populations and therapeutic protocols results in conflicting findings overall. Key Messages: The presence of VH should be taken into account when counseling a patient with NMIBC, since it may upgrade the disease to high-risk tumor and thus warrant a more aggressive treatment.

The optimal management of variant histology in muscle invasive bladder cancer

Bladder cancer is a heterogenous disease that is associated with tangible mortality in muscle invasive disease. The WHO 2016 classification of urothelial tumours reflects the contemporary approach towards histological variants in bladder cancer, including variants of urothelial carcinoma (UC) and non-urothelial variants. This review focuses on variant histology in UC, and discusses the importance of accurate histological diagnosis, and subsequent risk stratification and therapeutic decision making based on proper variant recognition. Most urothelial variants are associated with poorer outcomes compared to conventional UC, although some perform reasonably better. However, high quality evidence detailing optimal treatment and survival outcomes are still lacking in literature, due to the rarity of these cases.

Variant histology in bladder cancer: how it should change the management in non-muscle invasive and muscle invasive disease?

Bladder cancer (BC) is a frequent type of carcinoma with an estimated incidence of approximately 100,000 men and women each year in the European Union (EU) with an associated mortality of 30,000 of these patients. In more than 70% the disease is diagnosed in a non-muscle invasive stage with the chance of minimally invasive, local treatment only, which might be required repetitively due to high rate of recurrence. In contrast, muscle invasive or metastatic stages need multimodal treatment strategies including surgical treatment and chemotherapy (CTX) in neoadjuvant (NAC), adjuvant, or palliative settings. Therapy recommendations and guidelines mainly refer to the most common histological type of BC, pure urothelial carcinoma (UC). However, BC can be classified as urothelial and non-UC. Non-urothelial BC and variants of UC account for up to 25% of all BCs. Further discrimination can be made into epithelial and non-epithelial non-UC. Most of the non-UCs are of epithelial origin (approximately 90%) including squamous-cell carcinoma, adenocarcinoma and small-cell carcinoma. Non-epithelial tumors are rare and include variants as sarcoma, carcinosarcoma, paraganglioma, melanoma and lymphoma. Even though it is unclear whether the prognosis of non-urothelial cancer truly differs from that of UC, there is evidence that additional variant histology might prognosticate an impaired prognosis. Accordingly, aggressive behavior and often advanced stages at primary presentation are frequently observed in non-UC arguing for radical and sometimes different treatment strategies as compared to pure UC. This review aims to summarize the available data for the most common histological variants of non-urothelial BC.

The prognostic role of lymphovascular invasion in urothelial carcinoma of the bladder

Outcome prediction in patients with bladder cancer has improved through the development of nomograms and predictive models. However, integration of further characteristics such as lymphovascular invasion (LVI) might increase the accuracy and clinical utility of these instruments. Assessment and reporting of LVI in specimens from transurethral resection of the bladder tumour (TURBT) or biopsy in patients with non-muscle-invasive bladder cancer (NMIBC) or muscle-invasive bladder cancer (MIBC) might enable improved staging, prognostication and clinical decision-making. In NMIBC, presence of LVI in TURBT and biopsy samples seems to be associated with understaging and increased risks of disease recurrence and progression. In MIBC, presence of LVI is associated with features of aggressive disease and predicts recurrence and survival. Integration of LVI status into predictive models might aid clinical decision-making regarding intravesical instillation schedules and regimens, early radical cystectomy in patients with high-grade T1 disease and perioperative chemotherapy. However, LVI assessment is hampered by insufficient reproducibility and reliability, lack of routine evaluation and limited concordance between findings in TURBT and radical cystectomy specimens. Standardization of the pathological criteria defining LVI is warranted to improve its reporting in routine clinical practice and its utility as a care-changing prognostic marker.