Extranodal extension in node-positive bladder cancer: the continuing controversy

Extranodal Extension Predicts Poor Survival Outcomes among Patients with Bladder Cancer

BACKGROUND

Several lymph node-related prognosticators were reported in bladder cancer patients with lymph node involvement and receiving radical cystectomy. However, extranodal extension (ENE) remained a debate to predict outcomes.

METHODS

A retrospective analysis of 1303 bladder cancer patients receiving radical cystectomy and bilateral pelvic lymph node dissection were identified in the National Taiwan Cancer Registry database from 2011 to 2017. Based on the 304 patients with lymph node involvement, the presence of ENE and major clinical information were recorded and calculated. The overall survival (OS) and cancer-specific survival (CSS) were estimated with Kaplan-Meier analysis and compared using the log-rank test. Hazard ratios (HR) and the associated 95% confidence intervals were calculated in the univariate and stepwise multivariable models.

RESULTS

In the multivariable analysis, ENE significantly reduced OS (HR = 1.74, 95% CI 1.09-2.78) and CSS (HR = 1.69, 95% CI 1.01-2.83) more than non-ENE. In contrast, adjuvant chemotherapy was significantly associated with better OS and CSS upon the identification of pathological nodal disease.

CONCLUSIONS

Reduced OS and CSS outcomes were observed in the pathological nodal bladder cancer patients with ENE compared with those without ENE. After the identification of pathological nodal disease, adjuvant chemotherapy was associated with better survival outcomes.

The Usefulness of Lymphadenectomy in Bladder Cancer-Current Status

The purpose of this review is to present the current status of lymph node dissection (LND) during radical cystectomy in patients with bladder cancer (BCa). Despite the growing body of evidence of LND utility at the time of radical cystectomy (RC) in high-risk nonmuscle-invasive and muscle-invasive BCa (MIBC), therapeutic and prognostic value and optimal extent of LND remain unsolved issues. Recently published results of the first prospective, a randomized trial assessing the therapeutic benefit of extended versus limited LND during RC, failed to demonstrate survival improvement with the extended template. Although LND is the most accurate staging procedure, the direct therapeutic effect is still not evident from the current literature, limiting the possibility of establishing clear recommendations. This indicates the need for robust and adequately powered clinical trials.

Lymphadenectomy for Muscle-Invasive Bladder Cancer and Upper Tract Urothelial Cell Carcinoma

There are currently no reported randomized trials that characterize the staging or therapeutic benefit of performing a lymph node dissection in either bladder cancer or upper tract urothelial carcinoma. Several unanswered questions remain in this domain focused on the indications and patient selection for pelvic lymph node dissection, extent of dissection, its impact on outcome, and potential risks. However, the results of observational studies suggest that the burden of metastasis is high in both diseases when muscle invasive and performing a lymphadenectomy can provide prognostic information and yield therapeutic benefit.

Lymph node density vs. the American Joint Committee on Cancer TNM nodal staging system in node-positive bladder cancer in patients undergoing extended or super-extended pelvic lymphadenectomy

PURPOSE

We compared the prognostic value of the American Joint Committee on Cancer (AJCC) TNM nodal staging system with that of lymph node (LN) density in patients with LN-positive bladder cancer who received extended or super-extended pelvic lymphadenectomy.

METHODS

Of the 1,018 patients, who underwent radical cystectomy and pelvic lymphadenectomy between February 2005 and August 2014, 110 patients with LN metastases with extended (n = 68) or super-extended (n = 42) pelvic lymphadenectomy were included. All patients were staged using the 2002 (sixth edition) and 2010 (seventh edition) AJCC TNM staging systems. The association of several variables with recurrence-free survival (RFS) and overall survival (OS) was evaluated.

RESULTS

The median number of total LNs removed was 29 (6-118) and the median LN density was 12.5% (1.6%-100%). RFS and OS were not significantly different between the 2002 (pN1-pM1) and 2010 (pN1-N3) AJCC TNM nodal staging systems (sixth edition: P = 0.512 and P = 0.519; seventh edition: P = 0.676 and P = 0.671, respectively). The 2-year RFS and OS rates according to the LN density quartiles were 58.5% and 76.9% in Q1, 39.1% and 70.8% in Q2, 28.8% and 50.1% in Q3, and 12.7% and 20.8% in Q4 (P = 0.001 and P = 0.001, respectively). Multivariate analysis adjusted for the 2010 AJCC TNM staging system showed that LN density was associated with a decreased OS (HR = 1.024; 95% CI: 1.010-1.039; P = 0.001). The nodal staging system (2002 or 2010) was not associated with the RFS and OS.

CONCLUSIONS

LN density shows a better prognostic value than the AJCC TNM nodal staging system in patients with LN-positive bladder cancer receiving extended or super-extended pelvic lymphadenectomy.

Extracapsular Extension of Pelvic Lymph Node Metastasis is an Independent Prognostic Factor in Bladder Cancer: A Systematic Review and Meta-analysis

PURPOSE

We aimed to elucidate the relation between extracapsular extension (ECE) and clinical outcomes in node-positive patients following radical cystectomy for bladder cancer.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched PubMed, SCOPUS, Web of Science, and Cochrane Library databases from their respective dates of inception until September 2014.

RESULTS

Ten articles that met the eligibility criteria included 43-748 subjects per study, with the total number of patients being 1,893. The frequency of ECE ranged from 36.6 to 58.1 %. The pooled hazard ratio (HR) was statistically significant for recurrence-free survival (RFS) [pooled HR 1.56; 95 % confidence interval (CI) 1.13-2.14] and cancer-specific survival (CSS) (pooled HR 1.60; 95 % CI 1.29-1.99) but not overall survival (OS) (pooled HR 1.47; 95 % CI 0.71-3.05). Heterogeneity in RFS (I (2) 84 %, p < 0.00001) and OS (I (2) 80 %, p = 0.03) was statistically significant. According to subgroup analysis with meta-regression analyses, "region" (pheterogeneity < 0.0001) and "analysis results" (pheterogeneity < 0.0001) were the sources of heterogeneity. Sensitivity analysis showed that omission of any study did not lead to a significant difference. No statistical evidence of publication bias regarding RFS or CSS was revealed among the studies using Begg's and Egger's tests.

CONCLUSIONS

This meta-analysis shows that ECE is an efficient prognostic factor for node-positive bladder cancer. However, large prospective studies are needed to confirm the clinical utility of ECE as an independent prognostic factor before these results can be applied clinically.

Lymph node-positive bladder cancer: surgical, pathologic, molecular and prognostic aspects

The presence of lymphatic metastasis is associated with markedly worse prognosis in patients with bladder cancer, although surgical resection and chemotherapy can still provide long-term survival for selected patients. The prognostic stratification of patients with positive lymph nodes has been broadly discussed in the current literature and a more extensive pelvic lymph node dissection and thorough pathologic assessment has been advocated. It is clear that stratification using the tumor node metastasis staging system is insufficient to adequately discriminate prognosis between patients with different lymph node involvement. Lymph node density and extranodal extension have been extensively investigated and appear to influence the prognosis of these patients. Molecular markers have been developed to improve the diagnosis of micrometastatic disease, and new targeted therapies have shown promising preclinical results and are now being tested in different clinical scenarios.

Pelvic lymph node dissection in the context of radical cystectomy: a thorough insight into the connection between patient, surgeon, pathologist and treating institution

Pelvic lymph node dissection (PLND) in patients with bladder cancer varies widely in extent, technique employed, and pathological workup of specimens. The present paper provides an overview of the existing evidence regarding the effectiveness of PLND and elucidates the interactions between patient, surgeon, pathologist, and treating institution as well as their cumulative impact on the final postoperative lymph node (LN) staging. Bladder cancer patients undergoing radical cystectomy with extended PLND appear to have better oncologic outcomes compared to patients undergoing radical cystectomy and limited PLND. Attempts have been made to define and assess the quality of PLND according to the number of lymph nodes identified. However, lymph node counts depend on multiple factors such as patient characteristics, surgical template, pathological workup, and institutional policies; hence, meticulous PLND within a defined and uniformly applied extended template appears to be a better assurance of quality than absolute lymph node counts. Nevertheless, the prognosis of the patients can be partially predicted with findings from the histopathological evaluation of the PLND specimen, such as the number of positive lymph nodes, extracapsular extension, and size of the largest LN metastases. Therefore, particular prognostic parameters should be addressed within the pathological report to guide the urologist in terms of patient counseling.

Lymph node density for patient counselling about prognosis and for designing clinical trials of adjuvant therapies after radical cystectomy

What's known on the subject? and What does the study add? Patients with positive lymph nodes at radical cystectomy have a poor prognosis. The actual outcome of patients varies based on many factors, among which lymph node density has emerged as being more informative than nodal status of TNM staging. We combined clinical data from two major cancer centres in the USA and identified patients with an adequate lymphadenectomy and no perioperative chemotherapy to understand the natural history of the disease. Using this information, we created prognostic tools incorporating lymph node density that can be used for risk stratification, patient counselling and clinical trial design.

OBJECTIVE

• To develop a clinical tool based on lymph node density (LND) for patient counselling after radical cystectomy and for design of clinical trials of adjuvant therapies after radical cystectomy.

PATIENTS AND METHODS

• Using pooled data from two comprehensive cancer centres, we identified patients with lymph node metastases after radical cystectomy who received an adequate lymph node dissection according to existing literature (resection of eight or more nodes). • Only patients who had not received neoadjuvant or adjuvant chemotherapy were included to ensure that prediction models were based on the natural course of the disease. • Thresholds for LND ranging from 5% to 35%, in 5% increments, were used to dichotomize the study population. Within each set of two groups, the Kaplan-Meier product-limit estimator was used to estimate disease-specific survival (DSS) for each group, and Cox proportional hazards regression was used to test the significance of differences in DSS between the group with higher LND and the group with lower LND. • Tables and graphs showing the relationship between LND categories and 2-year and 5-year estimated DSS were created to aid in clinical decision-making.

RESULTS

• LND was valuable as a tool for stratifying node-positive patients into different risk groups based on expected survival. • At each LND threshold from 10% to 35%, patients with higher LND had significantly worse DSS than patients with lower LND (P ≤ 0.001). • As expected, DSS in the higher-LND group worsened with each 5% increase in LND threshold: patients with LND > 35% had a 5-year DSS rate of 4%. • Using our data as a tool, multiple cut-offs can be employed to categorize patients into various risk groups with different risk. For example, patients with LND ≤ 10% have an estimated 5-year DSS rate of 61.9%, whereas patients with LND > 15% have an estimated 5-year DSS rate of 19.2%.

CONCLUSIONS

• Patients with node-positive bladder cancer have poor outcomes, and survival varies widely according to LND. • Categorical LND should be used to risk-stratify patients for counselling regarding prognosis. • Furthermore, categorical LND should be used as a tool for designing and reporting on clinical trials of adjuvant therapies.

Extranodal extension is a powerful prognostic factor in bladder cancer patients with lymph node metastasis

BACKGROUND

Lymph node metastasis (LNM) is the most powerful pathologic predictor of disease recurrence after radical cystectomy (RC). However, the outcomes of patients with LNM are highly variable.

OBJECTIVE

To assess the prognostic value of extranodal extension (ENE) and other lymph node (LN) parameters.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis of 748 patients with urothelial carcinoma of the bladder and LNM treated with RC and lymphadenectomy without neoadjuvant therapy at 10 European and North American centers (median follow-up: 27 mo).

INTERVENTION

All subjects underwent RC and bilateral pelvic lymphadenectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Each LNM was microscopically evaluated for the presence of ENE. The number of LNs removed, number of positive LNs, and LN density were recorded and calculated. Univariable and multivariable analyses addressed time to disease recurrence and cancer-specific mortality after RC.

RESULTS AND LIMITATIONS

A total of 375 patients (50.1%) had ENE. The median number of LNs removed, number of positive LNs, and LN density were 15, 2, and 15, respectively. The rate of ENE increased with advancing pT stage (p<0.001). In multivariable Cox regression analyses that adjusted for the effects of established clinicopathologic features and LN parameters, ENE was associated with disease recurrence (hazard ratio [HR]: 1.89; 95% confidence interval [CI], 1.55-2.31; p<0.001) and cancer-specific mortality (HR: 1.90; 95% CI, 1.52-2.37; p<0.001). The addition of ENE to a multivariable model that included pT stage, tumor grade, age, gender, lymphovascular invasion, surgical margin status, LN density, number of LNs removed, number of positive LNs, and adjuvant chemotherapy improved predictive accuracy for disease recurrence and cancer-specific mortality from 70.3% to 77.8% (p<0.001) and from 71.8% to 77.8% (p=0.007), respectively. The main limitation of the study is its retrospective nature.

CONCLUSIONS

ENE is an independent predictor of both cancer recurrence and cancer-specific mortality in RC patients with LNM. Knowledge of ENE status could help with patient counseling, clinical decision making regarding inclusion in clinical trials of adjuvant therapy, and tailored follow-up scheduling after RC.

Evaluation of different lymph node (LN) variables as prognostic markers in patients undergoing radical cystectomy and extended LN dissection to the level of the inferior mesenteric artery

OBJECTIVE

To evaluate the prognostic impact of lymph node (LN) variables in patients undergoing radical cystectomy (RC) and extended LN dissection.

PATIENTS AND METHODS

From January 2004 to January 2009, 167 patients with bladder cancer underwent RC and extended LN dissection to the level of the inferior mesenteric artery in a surgery-only series with no neoadjuvant or adjuvant chemotherapy. Correlation to prognosis of different LN variables according to presence of LN metastasis, number, localization, extracapsular extension (ECE), size, volume, LN density and N-stage according to two different Tumour-Node-Metastasis (TNM) classifications were analysed.

RESULTS

In all, 43 patients (26%) had LN metastases. In univariate analysis, gender, T-stage and several different LN variables stratified by presence of LN metastasis, number of positive LNs, anatomical localisation, ECE, LN density, size and volume of positive LNs, were significant prognostic predictors. Female gender, advanced T-stage, presence of LN metastasis, non-regional LN metastases (M-positive) and number of positive LNs (1 vs >1) were significant adverse prognostic predictors in multivariate analysis, whereas the other LN variables were not. Inclusion of the common iliac LNs in the regional LNs as suggested in the seventh edition of the TNM classification was relevant regarding prognosis. However, subclassification based on location was not correlated to prognosis. The new N3 category therefore seems superfluous.

CONCLUSIONS

LN-positive patients have a poor prognosis, especially if >1 positive LN is present. Despite several different suggestions of new LN-dependent prognostic factors, none of the tested variables were independently significant in the present series.