Validation of the Eighth AJCC New Substages for Bladder Cancer Among Different Staging Contexts.

OBJECTIVES: To validate the prognostic value of the new American Joint Committee on Cancer (AJCC) staging system (eighth edition) among different staging contexts (clinical vs. pathologic).

METHODS: Surveillance, Epidemiology, and End Results (SEER) database (2010-2014) was accessed through SEER*Stat program and both AJCC seventh and eighth edition stages were assigned for each patient. Overall and cancer-specific survival analyses according to both editions were conducted through Kaplan-Meier analysis. Concordance index (c-index) was assessed for each edition.

RESULTS: A total of 7074 patients with pathologically staged and 26,698 with clinically staged urinary bladder carcinoma were identified in the period from 2010 to 2014. Among patients with pathologically staged disease without neoadjuvant treatment, P values for all pairwise comparisons among different stages (according to AJCC seventh and eighth systems) were significant for both overall and cancer-specific survivals (< .01). Moreover, within the same cohort, c-index (using death from urinary bladder cancer as the dependent variable) for AJCC seventh system was 0.714 (SE 0.008; 95% CI, 0.699-0.729); whereas the c-index for the AJCC eighth system was 0.718 (SE 0.008; 95% CI, 0.702-0.733). Likewise, among patients with clinically staged disease, P values for all pairwise comparisons among different AJCC eighth stages were significant for overall survival (< .05) except for stage IIIA versus stage IIIB; whereas P values for all pairwise comparisons among different AJCC eighth stages were significant for cancer-specific survival (P < .05).

CONCLUSION: This analysis supports the prognostic relevance of the added substages described within AJCC eighth edition stages III and IV for clinically staged and pathologically staged disease without neoadjuvant treatment.