Conditional survival of trimodal therapy for nonmetastatic muscle‐invasive bladder cancer: A SEER database analysis

OBJECTIVE: Conventional survival analysis plays a limited role in patients who have survived a period after initial treatment. The present study analyzed how conditional survival (CS) predicted survival rate over time for nonmetastatic muscle‐invasive bladder cancer (MIBC) patients after trimodal treatment. METHOD: This retrospective study from the SEER database included consecutive patients with nonmetastatic MIBC who received trimodal therapy (TMT) between January 2010 and December 2017. Kaplan‐Meier analysis was used to estimate overall survival (OS) and cancer‐specific survival (CSS). CS was defined as the rate of surviving y years after already surviving for x years. Multivariate Cox regression analysis was used to identify prognostic factors. RESULT: A total of 1110 nonmetastatic MIBC patients treated with TMT were included. Given a 1‐, 2‐, 3‐, and 4‐year after TMT, the rate of surviving to 5‐year, respectively, improved by +5.0 (20.0%), +17.0 (32.0%), +30.0 (45.0%), and +52.8 (67.8%) from those calculated at baseline (15.0%). The 2‐year CS rate of patients who had survived 1‐, 2‐, or 3‐year after TMT improved, respectively, compared to 3‐, 4‐, or 5‐year actual survival. Multivariate Cox regression analysis demonstrated that adverse variables (T stage, age) of OS and CSS lost their prognostic significance over time. DISCUSSION AND CONCLUSION: Conditional survival rate of surviving to 5‐year after TMT kept a relatively stable level over time. In addition, those adverse variables were not always the prognostic factors over time. Only age was always the significant prognostic factor for conditional OS from baseline to 5‐year survival. Our results provided real‐time survival information and prognosis estimates to adjust follow‐up plans for nonmetastatic MIBC patients after TMT.