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

ABSTRACT

ABSTRACT 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.