Critical Evaluation of the American Joint Committee on Cancer TNM Nodal Staging System in Patients with Lymph Node-Positive Disease after Radical Cystectomy

Background

The current 7th edition of the American Joint Committee on Cancer TNM staging system for bladder cancer stages lymph node (LN)–positive disease based on LN location rather than LN size. In addition, common iliac LNs are now considered regional LNs. Whether these changes improve prognostication for node-positive patients, however, remains unclear.

Objective

To investigate whether the 7th edition of the TNM nodal staging system provides superior prognostication compared with the 6th edition.

Design, setting, and participants

Patients between 2002 and 2008 with LN metastases after radical cystectomy combined with extended or superextended LN dissection were included. Patients were staged using both TNM staging systems. Median follow-up was 54 mo.

Outcome measurements and statistical analysis

Kaplan-Meier curves were used to estimate overall survival (OS) and recurrence-free survival (RFS). Log-rank tests and Cox proportional hazard regression models were used to test associations of pathologic variables with OS and RFS.

Results and limitations

Included were 146 patients with LN metastases of whom 131 patients underwent superextended LN dissection and 15 patients underwent extended LN dissection. Although in the 7th TNM edition many patients moved from the N2 category to the N3 category, RFS did not significantly differ within the nodal subgroups in either editions. LN metastases at or above the aortic bifurcation were not associated with decreased RFS (p = 0.67). On multivariable analysis, the presence of extravesical disease (hazard ratio [HR]: 2.84; p = 0.002), absence of adjuvant chemotherapy (HR: 0.32; p < 0.0001), and more than six positive LNs (HR: 2.72; p = 0.007) were associated with decreased RFS. This was a retrospective study with inherent limitations.

Conclusions

LNs at or above the aortic bifurcation should be considered regional LNs. Neither the 6th nor the 7th TNM staging system performed well as a prognostic tool. A better staging system for LN-positive bladder cancer needs to be developed.