Background: Acute kidney injury (AKI) is a frequent complication in patients with muscle-invasive bladder cancer (MIBC) who undergo radical cystectomy (RC). Previous studies have reported that AKI during cancer treatment was associated with poor oncological outcomes in several malignancies. Moreover, we previously have reported the negative impact of neoadjuvant chemotherapy-induced AKI on oncological outcomes in patients with MIBC. However, the impact of perioperative AKI on oncological outcomes in patients who undergo RC remains unclear. Methods: This multi-institutional retrospective study included 798 patients with MIBC who underwent RC. AKI was defined according to the KDIGO criteria. Stage 1 AKI was diagnosed with an increase in serum creatinine by just 0.3 mg/dL. Patients were divided into two groups: patients who developed AKI after RC (AKI group) and patients who did not (non-AKI group). Multivariable Cox-proportional hazards regression analyses were performed to evaluate the impact of perioperative AKI on recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Results: The median age and follow-up period were 70 years and 64 months, respectively. Of the 798 patients, 408 (51%) developed AKI after RC. Approximately 73% AKI were stage 1 AKI. RFS, CSS, and OS in the AKI group were significantly shorter than those in the non-AKI group (P = 0.003, P = 0.035, and P< 0.001, respectively). After adjustment for confounding variables, AKI was significantly associated with shorter RFS (hazard ratio [HR] 1.357, P = 0.019), CSS (HR 1.345, P = 0.042), and OS (HR 1.344, P = 0.009). Conclusions: Perioperative AKI was associated with poor oncological outcomes in patients with MIBC who underwent RC.

*Adjusted for age, performance status, neoadjuvant chemotherapy, tumor grade, variant histology, pathological T stage, lymphovascular invasion, pathological lymph node involvement, positive surgical margin, and neobladder reconstruction. CI, confidence interval.