Renal function change after radical cystectomy for urothelial carcinoma patients with a solitary kidney may be independent of urinary diversion type

PURPOSE: To compare renal function change by urinary diversion (UD) type (ileal conduit [IC] vs. neobladder [NB]) in patients with a single kidney who underwent radical cystectomy (RC) due to bladder cancer. MATERIALS AND METHODS: We evaluated the renal function change in 86 patients with a single kidney who underwent RC between January 1999 and August 2022. Renal function was assessed using serum creatinine, serum estimated glomerular filtration rate (eGFR), eGFR difference value (preoperative and follow-up values), and eGFR difference proportion (eGFR difference value/preoperative eGFR) at 1, 3, 6, 12, 24, 36, 48, and 60 months. In addition, multiple definitions of eGFR decline were evaluated: 10 points, 10%, and 20% decline in eGFR. Cox regression models were used to identify risk factors of eGFR decline-free, recurrence-free, overall, and cancer-specific survival rates. RESULTS: A total of 54 patients (62.8%) underwent IC, whereas 32 (37.2%) underwent NB. Baseline characteristics were similar between the two groups except for age and body mass index. Renal functions over time by various methods did not differ significantly between the IC and NB groups. Furthermore, eGFR decline-free survival rate using different definitions was similar between the IC and NB groups. Overall survival, recurrence-free survival, and cancer-specific-free survival rates were not different between the IC and NB groups. CONCLUSIONS: UD type (IC vs. NB) did not impact the renal function change of patients with a single kidney who underwent RC. Therefore, patients with a single kidney might be considered to be an indication of NB.