The impact of second transurethral resection on survival outcomes in patients with non-muscle-invasive bladder cancer treated with bacillus Calmette–Guérin therapy

Abstract

Objective Several guidelines recommended that second transurethral resection should be performed in patients with diagnosis of high-risk non-muscle-invasive bladder cancer. However, therapeutic benefits of second transurethral resection before bacillus Calmette–Guérin intravesical instillation were conflicting amongst previous studies. We investigated the prognostic impact of second transurethral resection before bacillus Calmette–Guérin instillation in high-risk non-muscle-invasive bladder cancer patients. Methods This retrospective study included 3104 non-muscle-invasive bladder cancer patients who received bacillus Calmette–Guérin instillations between 2000 and 2019 at 31 collaborative institutions. Univariate and multivariate Cox proportional hazards models were used to assess the risk factors of intravesical recurrence, disease progression, cancer-specific mortality and overall mortality. Results In the entire population, patients undergoing second transurethral resection (33%, 1026/3104) had a lower risk of intravesical recurrence on univariate analysis (hazard ratio 0.85, 95% confidence interval 0.73–0.98, P = 0.027), although it did not remain significant on multivariate analysis (hazard ratio 0.90, 95% confidence interval 0.76–1.07, P = 0.24). Subgroup analysis revealed that, in pT1 patients (n = 1487), second transurethral resection was significantly correlated with a lower risk of intravesical recurrence on multivariate analysis (hazard ratio 0.80, 95% confidence interval 0.64–1.00, P = 0.048), but lower risks of disease progression (hazard ratio 0.75, 95% confidence interval 0.56–1.00, P = 0.049), cancer-specific mortality (hazard ratio 0.54, 95% confidence interval 0.35–0.85, P = 0.007) and overall mortality (hazard ratio 0.73, 95% confidence interval 0.55–0.97, P = 0.027) on univariate analysis. Conclusions Second transurethral resection confers accurate pathological staging and could be used to safely select good candidates for intravesical bacillus Calmette–Guérin instillation. We further confirm that second transurethral resection could confer an oncological benefit in pT1 bladder cancer patients treated by bacillus Calmette–Guérin instillation, and so strongly recommend second transurethral resection in this patient population.