Analysis of sarcopenia indicators on survival prediction undergoing radical cystectomy

Background: Sarcopenia is increasingly recognized as an imaging-based prognostic factor in various cancers, but its gender-specific radiological indicators in bladder cancer patients undergoing radical cystectomy are not well defined. Objective: The aim of this study was to identify the radiological sarcopenia parameters that can be used to predict overall survival(OS) in patients who underwent radical cystectomy(RC). Methods: The data of a total of 183 patients who underwent RC for urothelial bladder cancer and had an abdominal computed tomography(CT) scan within three months prior to surgery, were retrospectively analyzed. Skeletal muscle areas at the L3 vertebral level and average Hounsfield unit(HU) measurements were extracted from the CT images.Based on these measurements, five sarcopenia-related parameters [skeletal muscle index (SMI) type 1, SMI type 2, psoas muscle index(PMI) type 1, PMI type 2, and skeletal muscle density(SMD)] were calculated and investigated their prognostic effect on OS using uni- and multi-variable Cox regression analysis. Results: The median follow-up period was 22 months(IQR: 10-50).In univariate Cox regression analysis, significant factors affecting overall survival in men included age, pT stage, pN stage, SMI type 1, SMI type 2, and PMI type 2(p < 0.05).In women, significant factors included pT stage, pN stage, and only SMD(p < 0.05).Among radiologic sarcopenia markers, multivariate Cox regression models indicated that significance of the SMI type 1, the SMI type 2 and the PMI type 2 remained as prognostic factors for overall survival in men(p < 0.05). In women, only SMD remained significant(p = 0.018). Conclusions: Our analysis highlighted that gender-specific radiological sarcopenic parameters impact on OS among patients undergoing RC.SMI type 1, SMI type 2, and PMI type 2 for male and only SMD for female were prognosticators in patients undergoing RC.