Neoadjuvant Cisplatin-Based Chemotherapy In Patients With Ureteral Obstruction Secondary To Muscle Invasive Bladder Cancer

523 Background: Neoadjuvant cisplatin-based chemotherapy (NAC) followed by cystectomy is the standard of care for muscle-invasive urothelial bladder cancer (MIBC). 15-35% of MIBC patients present with ureteral obstruction. Poor renal function increases cisplatin toxicity. It is unknown whether patients with ureteral obstruction which has been relieved (whether by nephrostomy tube or nephroureteral stent) have the same risk of toxicity as patients without ureteral obstruction. Methods: We retrospectively reviewed an institutional database of all patients undergoing NAC for MIBC with either dose dense MVAC (ddMVAC) or gemcitabine and cisplatin (GC) from January 2004 through May 2017. Patients without ureteral obstruction prior to initiation of NAC (Group A) were compared to those who had ureteral obstruction which was relieved prior to undergoing NAC (Group B). Continuous variables were compared using the Wilcoxon rank-sum test and categorical variables were compared using Fisher’s exact test. The primary outcome was premature discontinuation of NAC, which was defined as failure to complete all planned cycles. Logistic regression was used to test for differences between the groups in this outcome adjusting for age, ECOG performance status, and baseline glomerular filtration rate (GFR). Results: 160 patients in Group A and 59 patients in Group B were identified. Baseline age, Charlson Comorbidity Index, race, smoking status, and ECOG performance status were similar. Patients in Group B had lower GFR (99.2% vs 78.8% p <0.001) and were more likely to be female (21.9% vs 27.3% p <0.025) and to receive ddMVAC (65.0% vs. 83.1% p =0.012). There was no significant difference between groups in rates of premature NAC discontinuation (15.8% vs 22.0% p = 0.284) or grade ≥3 adverse events (23.4% vs 30.5% p = 0.285). Adjusted analysis showed no significant difference between the groups in frequency of premature NAC discontinuation (OR 1.96, 95% CI 0.84-4.57 p=0.12). Conclusions: We detected no difference in frequency of premature discontinuation of NAC in patients with relieved malignant ureteral obstruction relative to patients without obstruction. NAC for MIBC is likely safe in this population.