Optimal timing of radical cystectomy after neoadjuvant chemotherapy in muscle invasive bladder cancer (MIBC).

Abstract

509 Background: Neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) with bilateral pelvic lymph node dissection is the current standard of care for MIBC. Pathologic downstaging with NAC is an important surrogate endpoint and associated with overall survival benefit. There have been questions about the impact of delay in definitive surgery because of NAC. The optimal timing of surgery from the start of NAC is uncertain. We studied this question using National Cancer Database (2004-2015). Methods: We identified patients with MIBC (cT2-T4aN0M0 & cT1-T4aN1M0) who received NAC within 6 months of diagnosis and underwent surgery between 10 weeks and 9 months of the start day of NAC. We excluded patients who died within 30 days of surgery. Time period was stratified into three cohorts; 11-16, 17-24, and ≥25 weeks from the start day of NAC. Descriptive analysis, Kaplan-Meier plots, Log-Rank tests for univariate and proportional hazards models for multivariate survival analyses were performed. Results: 3709 patients were identified; 75% were males, 77% cases were cT2 and 73% had charlson-deyo score (CS) of '0'. Median time for surgery 10 weeks after start of NAC was 118 days. Forty-two (42%) had surgery in 11-16, 47% in 17-24 and 9.9% in ≥25 weeks. Majority (60%) were treated at academic and 24% at comprehensive community. Only 29% achieved complete pathological complete response rate (Tis or T0). On univariate analysis receiving NAC within 3 months of diagnosis was significantly associated with survival benefit (p < 0.001). Cox-regression results showed that patients who underwent surgery in 11-16 and 17-24 week time period had significantly better survival than > 25 week group with HR of 0.84 (0.71- 0.98) and 0.82 (0.70-0.97) respectively. In addition patients with CS of '0' had better survival with HR 0.78 (0.62-0.90) and > 75 years of age was associated with worse survival HR 1.73 (1.35-2.22). Conclusions: Our study indicates that appropriate patients with MIBC benefit from receiving surgery within 24 weeks of starting NAC. However, randomized prospective study is warranted to further explore the role of delay of surgery from NAC.