Downstaging and Survival Associated with Neoadjuvant Immunotherapy Before Radical Cystectomy for Muscle-invasive Bladder Cancer

Background: Neoadjuvant cisplatin-containing chemotherapy before radical cystectomy is the standard of care for patients with localized muscle-invasive bladder cancer (MIBC). However, a large proportion of patients are ineligible for cisplatin. Single -arm phase 2 neoadjuvant immunotherapy trials have reported promising tumor response rates, but interpretation is limited owing to lack of a comparator arm. Objective: To compare rates of pathologic downstaging and overall survival between patients receiving neoadjuvant immunotherapy (NAI), neoadjuvant chemotherapy (NAC), or no neoadjuvant therapy (NNAT). Design, setting, and participants: We identified 18 483 patients in the National Cancer Data Base who were diagnosed with clinically localized MIBC and underwent radical cystectomy from 2014 to 2019. Outcome measurements and statistical analysis: Nearest-neighbor propensity-score caliper matching was used to create three demographically similar and equally sized cohorts stratified by NAT receipt. Logistic regression was used to examine the association of treatment received with pathologic downstaging to pT0N0 and pT < 2N0. Cox proportional-hazards regression was used to assess the association of treatment received with overall survival (OS). Results and limitations: Propensity score matching yielded three equally sized cohorts without significant differences in baseline characteristics (n = 840). The NAI group had a higher rate of pathologic downstaging to pT0N0 than the NNAT group and a similar rate to the NAC group (NNAT 6.7% vs NAC 26.4%, odds ratio 5.0, 95% confidence interval [CI] 2.9-8.3; NAI 22.5%, odds ratio 4.0, 95% CI 2.4-7.1). The NAI group had better OS than the NNAT group and similar OS to the NAC group (NAC: hazard ratio 0.62, 95% CI 0.42- 0.92; NAI: hazard ratio 0.68, 95% CI 0.46-0.97, with NNAT as the reference). The primary limitation is selection bias from confounding by clinical indication. Conclusions: NAI is a promising alternative to NAC for patients with clinically localized MIBC, as evidenced by similar pathologic downstaging rates and OS benefits in comparison to no NAT. Phase 3 trials should be conducted to test the noninferiority of NAI to NAC.