External Validation of Extranodal Extension and Lymph Node Density as Predictors of Survival in Node-positive Bladder Cancer after Radical Cystectomy

Abstract

Prognostic factors in pathologic node-positive patients after radical cystectomy are debated. Extranodal extension (ENE) and lymph node density (LND) are strong predictors of survival. The aim of this study was to assess factors predictive of survival and to evaluate the prognostic significance of the tumor, node, metastasis staging system (TNM) nodal classification in a retrospective cohort of node-positive bladder cancers after radical cystectomy. We retrospectively reviewed the data of 75 patients with node-positive bladder cancer after radical cystectomy. Node pathological examination was performed by two experienced uropathologists. Cox regression analysis was performed to identify factors predictive of progression. The median number of removed lymph node was 18 (range 3-49). The median number of positive lymph nodes was 3 (range 1-35). Overall progression-free and cancer-specific survival were 5 and 12%. In multivariate analysis, ENE, LND with a 20% cutoff, and adjuvant chemotherapy were independent predictors of progression-free survival (p=0.007, 0.006, <0.0001). Neither the 2002 nor the 2009 TNM nodal classification was associated with recurrence. ENE and LND are strong predictors of clinical outcome in patients with node-positive bladder cancer treated by cystectomy. The actual TNM classification could probably be improved using these criteria, allowing better prognostic classification of node-positive bladder cancer after radical cystectomy.