770PImpact of sarcopenia and adiposity in survival of metastatic esophageal cancer (MEC)

Abstract Background Multiple mechanisms can directly influence body compositions (bcomp) in cancer: tumor-dependent chronic inflammation, leading to (a) anorexia and multiple neuroendocrine changes, (b) patient-dependent treatment related effects, and (c) in esophageal cancer, mechanical alterations with weight loss. Supportive management depends on understanding the cancer frailty determinants that lead to poor outcomes. Methods We retrospectively identified MEC patients (pts) treated in Toronto, Canada (2007-2014). Bcomp was assessed at presentation, using computed tomography, and included skeletal muscle index (SMI), visceral (VA) and subcutaneous adiposity (SA). Two outcome-blinded radiologists (Intraclass correlation, 0.92-1.00) assessed the L3 level, using SliceOMatic software. Published sex and BMI-dependent Bcomp cut-offs were used to define cancer associated sarcopenia. Cox proportional hazard models generated adjusted hazard ratios (aHR) and Kaplan-Meier curves estimated survival. Results Of 127 pts, 83% were male; 94% Caucasian; median age at diagnosis 61y (29-88); 80% were stage IV de novo. Mean body mass index (BMI) was 24.7; 69%/27%/3% were adeno/squamous cell /large cell carcinoma. Median overall (OS) and progression free survival (PFS) were: 6.4 (OS) and 1.5 mos (PFS). Median follow-up time was 5.6 mos. 49% were sarcopenic at baseline; of 44 pts with BMI > =25, 41% were sarcopenic. Univariable analyses identified albumin, LDH, and arcopenia as being inversely associated with OS and PFS. Multivariable models showed that sarcopenia was independently associated with worse OS (aHR=1.74, 95%CI 1.06-2.86, p = 0.03), and worse PFS (aHR=1.95, 95%CI 1.10-3.44, p = 0.02). In 76 pts receiving chemotherapy at diagnosis, less total adiposity (VA+SA) showed a trend towards worse OS (aHR=0.99 95%CI 0.99-1.00 p = 0.07 as continuous variable). Conclusions Sarcopenia at baseline is inversely related with OS and PFS in MEC. Our MEC patients had a higher incidence of sarcopenic obesity compared to cancer populations in the literature (9%). Future studies are needed to better characterize muscle and adiposity underlying biological importance in MEC. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.