Critical analysis of the 2010 TNM classification in patients with lymph node–positive bladder cancer: Influence of lymph node disease burden

Prognostic nomogram based on the lymph node metastasis indicators for patients with bladder cancer: A SEER population‐based study and external validation

PURPOSE

This study aimed to compare the prognostic value of multiple lymph node metastasis (LNM) indicators and to develop optimal prognostic nomograms for bladder cancer (BC) patients.

METHODS

BC patients were obtained from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015, and randomly partitioned into training and internal validation cohorts. Genomic and clinical data were collected from The Cancer Genome Atlas (TCGA) as external validation cohort. The predictive efficiency of LNM indicators was compared by constructing multivariate Cox regression models. We constructed nomograms on basis of the optimal models selected for overall survival (OS) and cause-specific survival (CSS). The performance of nomograms was evaluated with calibration plot, time-dependent area under the curve (AUC) and decision curve analysis (DCA) in three cohorts. We subsequently estimated the difference of biological function and tumor immunity between two risk groups stratified by nomograms in TCGA cohort.

RESULTS

Totally, 10,093 and 107 BC patients were screened from the SEER and TCGA databases. N classification, positive lymph nodes (PLNs), lymph node ratio (LNR) and log odds of positive lymph nodes (LODDS) were all independent predictors for OS and CSS. The filtered models containing LODDS had minimal Akaike Information Criterion, maximal concordance indexes and AUCs. Age, LODDS, T and M classification were integrated into nomogram for OS, while nomogram for CSS included gender, tumor grade, LODDS, T and M classification. The nomograms were successfully validated in predictive accuracy and clinical utility in three cohorts. Additionally, the tumor microenvironment was different between two risk groups.

CONCLUSIONS

LODDS demonstrated superior prognostic performance over N classification, PLN and LNR for OS and CSS of BC patients. The nomograms incorporating LODDS provided appropriate prediction of BC, which could contribute to the tumor assessment and clinical decision-making.

Development and Validation of a Prognostic Nomogram for Predicting Cancer-Specific Survival in Patients With Lymph Node Positive Bladder Cancer: A Study Based on SEER Database

Purpose

To construct a prognostic model to predict the cancer-specific survival (CSS) for bladder cancer patients with lymph node-positive.

Patients and Methods

We enrolled 2,050 patients diagnosed with lymph node-positive bladder cancer from the Surveillance Epidemiology and End Results (SEER) database (2004–2015). All patients were randomly split into development cohort (n = 1,438) and validation cohort (n = 612) at a ratio of 7:3. The univariate and multivariate Cox regression analysis were performed to identify prognostic factors. A nomogram predicting CSS was established based on the results of multivariate Cox analysis. Its performance was evaluated by calibration curves, the receiver operating characteristic (ROC) curves, and the concordance index (C-index). Internal verification was performed in the validation cohort. The Kaplan–Meier method with the log-rank test was applied in the different risk groups.

Results

The nomogram incorporated summary stage, tumor size, chemotherapy, regional nodes examined and positive lymph nodes. The C-index of the nomogram in the development cohort was 0.716 (0.707–0.725), while the value of the C-index was 0.691 (0.689–0.693) in the validation cohort. The AUC of the nomogram was 0.803 for 3-year and 0.854 for 5-year in the development cohort, while was 0.773 for 3-year and 0.809 for 5-year in the validation cohort. Calibration plots for 3-year and 5-year CSS showed good concordance. Significant differences were observed between high, medium, and low risk groups (P <0.001).

Conclusions

We have established a prognostic nomogram providing an accurate individualized probability of cancer-specific survival in bladder cancer patients with lymph node-positive. The nomogram could contribute to patient counseling, follow-up scheduling, and selection of treatment.

Staging of bladder cancer

Urothelial carcinoma of the urinary bladder is a heterogeneous disease with multiple possible treatment modalities and a wide spectrum of clinical outcome. Treatment decisions and prognostic expectations hinge on accurate and precise staging, and the recently published American Joint Committee on Cancer (AJCC) Staging Manual, 8th edition, should be the basis for staging of urinary bladder tumours. It is unfortunate that the International Union Against Cancer (UICC) 8th edition failed to incorporate new data which is considered in the AJCC 8th edition. Thus, the AJCC 8th edition is the focus of this review. Several critical changes and clarifications are made by the AJCC 8th edition relative to the 7th edition. Although the most obvious changes in the 8th edition are in the N (i.e. perivesical lymph node involvement now classified as N1) and M (i.e. M1 is subdivided into M1a and M1b) categories, several points are clarified in the T category (e.g. substaging of pT1 should be attempted). Further optimisation, however, is required. No particular method of substaging pT1 is formally recommended. In this review, these modifications are discussed, as well as points, which require further study and optimisation.

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.

Three-tiered nodal classification system for bladder cancer: a new proposal

ABSTRACT 

Aim: To evaluate a three-tiered prognostic stratification using one, two to five and >five positive lymph nodes (LNs) and this nodal staging system performs across different pelvic LN dissection (PLND) templates and adjuvant chemotherapy status. Methods: We evaluated 244 patients with positive LN urothelial cancer who underwent radical cystectomy and PLND between 2000 and 2011. Survival analyses utilizing the Kaplan-Meier method and log rank test were performed. Median follow-up was 55.3 months (range: 0.4–141). Multivariable Cox proportional hazards models were built to evaluate the prognostic stratification. Results: Extended PLND template was performed on 152 (62.3%) patients and standard on 92 (37.7%). The median number of LNs resected was 14 in the standard group vs 22 in the extended group (p < 0.01) and positive LNs was 2 vs 3 (p = 0.09), respectively. Stratification in patients with: one positive LN, two to five positive LNs or >five positive LNs lead to 5-year recurrence-free survival of: 48.6, 34.5 and 15.9% for each group, while the 5-year overall survival was: 43.0, 22.1 and 11.3%, respectively. Stratification in the three groups was also verified irrespective of PLND template and adjuvant chemotherapy. Two multivariable models confirmed the findings when controlling for demographic features and known pathologic risk factors. Conclusion: Three-tiered nodal classification system using the number of metastatic LNs (one, two to five and >five) stratifies patients with lymphatic disease into distinct prognostic groups.