Use of Gemcitabine plus Carboplatin is Associated with Poor Outcomes in Urothelial Carcinoma Patients with Chronic Kidney Disease Stage 4-5

This study aimed to investigate the clinical outcomes with gemcitabine-carboplatin (GCb), the standard treatment for patients with advanced urothelial carcinoma (UC) who are ineligible for cisplatin-based regimens, in advanced UC patients with a glomerular filtration rate (GFR) < 30 mL/min. A retrospective cohort study involving GCb-treated advanced UC patients with GFR < 60 mL/min (n=89) was performed. Clinical outcomes were compared between subgroups with GFR < 30 mL/min and GFR ≥ 30 mL/min but < 60 mL/min. Most baseline characteristics were comparable between the two subgroups. Patients with GFR < 30 mL/min had a significantly lower objective response rate (12.5%) compared to those with higher GFR levels (56.7%) (p=0.004). The number of GCb cycles was significantly lower in patients with GFR < 30 mL/min (median 2 cycles) than in those with higher GFR levels (median 6 cycles) (p=0.002). Compared to those with GFR ≥ 30 mL/min but < 60 mL/min, patients with GFR < 30 mL/min showed significantly worse progression-free survival (PFS) and overall survival (OS) (p < 0.001 for both). Further stratification of patient subgroups according to their GFR (i.e., GFR ≥ 45 mL/min but < 60 mL/min vs. GFR ≥ 30 mL/min but < 45 mL/min vs. GFR < 30 mL/min) revealed significantly different PFS and OS (p < 0.001 for both). The use of GCb is discouraged in advanced UC patients with GFR < 30 mL/min. Alternative therapeutic approaches with better efficacy are warranted for these patients.