Decrease in skeletal muscle index one year after radical cystectomy as a prognostic indicator in patients with urothelial bladder cancer

PURPOSE: The present study aimed to determine whether sarcopenia after radical cystectomy (RC) could predict overall survival (OS) in patients with urothelial bladder cancer (UBC). MATERIALS AND METHODS: The lumbar skeletal muscle index (SMI) of 80 patients was measured before and 1 year after RC. The prognostic significance of sarcopenia and SMI decrease after RC were evaluated using Kaplan–Meier analysis and a multivariable Cox regression model. RESULTS: Of 80 patients, 26 (32.5%) experienced sarcopenia before RC, whereas 40 (50.0%) experienced sarcopenia after RC. The median SMI change was -2.2 cm2/m2. Patients with sarcopenia after RC had a higher pathological T stage and tumor grade than patients without sarcopenia. Furthermore, the overall mortality rate was significantly higher in patients with sarcopenia than in those without sarcopenia 1 year after RC. The median follow-up time was 46.2 months, during which 22 patients died. Kaplan-Meier estimates showed a significant difference in OS rates based on sarcopenia (P=0.012) and SMI decrease (P=0.025). Multivariable Cox regression analysis showed that SMI decrease (≥2.2 cm2/m2) was an independent predictor of OS (hazard ratio: 2.68, confidence interval: 1.007-7.719, P = 0.048). CONCLUSIONS: The decrease in SMI after surgery might be a negative prognostic factor for OS in patients who underwent RC to treat UBC.