Neoadjuvant versus adjuvant chemotherapy in bladder cancer: a nationwide cohort study

Purpose Radical cystectomy is the standard of care for muscle-invasive bladder cancer. However, the 5-year survival rate is only about 50%. Therefore, additional treatments are needed. We compared the perioperative outcomes, overall survival, and treatment trends in patients with bladder cancer who underwent radical cystectomy and either neoadjuvant or adjuvant chemotherapy using nationwide population-based data. Materials and methods We collected the data of patients diagnosed with bladder cancer treated with radical cystectomy between 2004 and 2016 using the National Health Insurance Service database. We evaluated overall treatment trends. The neoadjuvant chemotherapy and adjuvant chemotherapy groups were matched by propensity score. Cox proportional hazard analysis and Kaplan-Meier analysis were used to assess survival. Results Of 6134 patients, 1379 underwent adjuvant chemotherapy and 389 underwent neoadjuvant chemotherapy. The utilization rate of neoadjuvant chemotherapy increased from 6.4 to 12.2% from 2004 to 2016 (p = 0.018). The administration rate and number of granulocyte colony-stimulating factor cycles were lower in the neoadjuvant chemotherapy group than in the adjuvant chemotherapy group (p < 0.001 and p = 0.027, respectively). After propensity score matching, the neoadjuvant chemotherapy group had significantly better overall survival than the adjuvant chemotherapy group (p = 0.004). In multivariate analysis, neoadjuvant chemotherapy was associated with better overall survival (hazard ratio 0.77, 95% confidence interval 0.65-0.92, p = 0.003). Conclusions Neoadjuvant chemotherapy was associated with lower granulocyte colony-stimulating factor administration and better overall survival than adjuvant chemotherapy. Neoadjuvant chemotherapy should be considered for patients with bladder cancer who undergo radical cystectomy.