Propensity-matched analysis of stage-specific efficacy of adjuvant chemotherapy for bladder cancer.

Background: Contemporary randomized controlled trials exploring adjuvant chemotherapy (AC) for bladder cancer (BCa) have yielded inconsistent results due to premature termination and/or poor patient accrual.
Objective: To compare efficacy of AC vs. observation after radical cystectomy stratified by disease stage in a propensity-matched cohort.
Design, Setting, and Participants: We performed a retrospective study that included patients who underwent radical cystectomy for any pT, N0-1, M0 BCa from the National Cancer Data Base (2004-2014). Patients who underwent AC were 1:1 propensity matched with patients who received observation only.
Outcome Measurements and Statistical Analysis: Overall survival was assessed with multivariable Cox regression models where adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) were calculated.
Results and Limitations: After coarsened exact 1:1 propensity matching, 3,066 patients (AC 1,533; observation 1,533) were included in the analysis. There were no significant differences in patient-, facility-, or tumor-level characteristics among cohorts. Compared with patients who underwent observation, recipients of AC had improved overall survival (aHR 0.67; 95% CI 0.61-0.74). Patients with pT2-4, pN1 disease significantly benefited from AC. Among the pN0 cohort, improved survival from AC was observed only in stages pT3 (aHR 0.67; 95% CI 0.55-0.83) and pT4 (aHR 0.70; 95% CI 0.50-0.98).
Conclusions: AC was associated with improved survival in locally advanced (pT3-4, pN0) and regionally advanced (pT2-4, pN1) chemotherapy-naive BCa.
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