DaBlaCa-17: nationwide observational study in Denmark on survival before and after implementation of neoadjuvant chemotherapy prior to cystectomy for muscle-invasive bladder cancer

Objective: To investigate the impact of neoadjuvant chemotherapy implementation with gemcitabine-cisplatin on survival outcomes for patients with muscle-invasive bladder cancer in Denmark.Materials and methods: Data were collected on all patients in Denmark undergoing radical cystectomy who were potential candidates for neoadjuvant chemotherapy from 2010 to 2015 (n = 851). A cohort before the implementation of neoadjuvant chemotherapy (Cohort 2010-12) was compared with a cohort after implementation (Cohort 2013-15). Patients in Cohort 2013-15 receiving neoadjuvant chemotherapy (+NAC, n = 213) were compared with patients in Cohort 2013-15 not receiving neoadjuvant chemotherapy (-NAC, n = 139). Pathological results after radical cystectomy and oncological outcomes were compared between the study cohorts. Overall survival, disease-free survival, and disease-specific survival were compared with Kaplan-Meier plots and with univariable and multivariable Cox regression. Kaplan-Meier estimates of overall survival were also performed separately for treating hospital and for pathological stage.Results: Pathological T0 (pT0) was more frequent in patients who received neoadjuvant chemotherapy: 34% versus 18% when comparing Cohort 2013-15 with Cohort 2010-12 (p < 0.001), and 46% versus 16% in +NAC compared with -NAC (p < 0.001). Overall survival, disease-free survival, and disease-specific survival at 5 years after cystectomy were not improved in Cohort 2013-15 compared with Cohort 2010-12 with adjusted hazard ratios of 1.11 (95% confidence interval [CI]: 0.87-1.43), 1.02 (95% CI: 0.81-1.29), and 1.06 (95% CI: 0.80-1.41), respectively.Conclusions: This observational study found no improved survival in a national cohort of patients with muscle-invasive bladder cancer undergoing radical cystectomy after implementation of NAC. However, reservations should be made regarding the study design and the true effect of NAC on survival outcomes