Assessment Of Sarcopenia As Predictor Of Response And Outcome After Neoadjuvant Chemotherapy (Nac) And Radical Cystectomy (Rc) In Muscle-Invasive Bladder Cancer (Mibc).

e15512 Background: Sarcopenia (loss of skeletal muscle mass) at the time of RC has been associated with lower cancer-specific and overall survival (OS) in bladder cancer patients. Change in muscle volume during NAC has not been well studied. We assessed change in total psoas muscle volume (TPMV) before and after NAC and evaluated if such change was associated with pathologic response at cystectomy, 2-year recurrence-free rate (2yRFR) or OS. Methods: During the period 2009-2013, patients with pure/mixed urothelial MIBC undergoing NAC and RC at Cleveland Clinic with pre and post NAC (prior to RC) cross sectional CT images available were selected from our IRB-approved RC database. Bilateral TPMV was obtained from pre and post NAC images by one observer (Radiology). The proportion of TPMV change was calculated by dividing the change in TPMV by pre-NAC TPMV. Univariate and multivariate analysis for assessment of factors predicting pathologic complete response (pCR, pT0N0), partial response (pPR, ≤ pT1N0), 2yRF...