CT-Defined Body Composition in Adult Patients with Hematological Malignancies Prior to Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT): Endemic Sarcopenia and Reduced Muscle Radiodensity Associate with Impaired Forced Expiratory Volume (FEV)1

Background Precise quantification of skeletal muscle using computed tomography is accessible using cancer patients' standard oncologic images. Reduced muscle mass (i.e. sarcopenia) has been related to mortality, treatment complications and QOL and reduced respiratory muscle strength, however these associations are not well characterized in adult alloHSCT recipients. Methods A consecutive retrospective series (n=296) patients who had allogeneic BMT at a comprehensive Center between 01/2016 and 12/2017. Pre-transplant CT scans were used to quantify skeletal muscle and adipose tissue at the 3rd lumbar (L3) and/or 4th thoracic (T4) vertebra. Tumor and patient characteristics were recorded, including FEV1 by spirometry. Sarcopenia was defined according to Prado et al. (PMID:18539529) Results 296 patients (male n=161; female n=135) were included, all of whom had thoracic-CT; a subset of these (n=195) also had lumbar-CT. Diagnoses were NHL (n=172), AML (n=66) HD (n=14), ALL (n=14), MDS (n=18) and other (MM, MPN, CML; n=12). Patients had increased BMI (male= 28.7 kg/m2, female=26.5 kg/m2), with many patients (♂64.7%; ♀57.0%) meeting criteria for sarcopenia. Rates of sarcopenia were higher (p Men and women were more muscular at T4 than L3. L3 and T4 skeletal muscle areas were moderately correlated (r2 =0.33- 0.47), as were L3 and T4 muscle radiodensities (r2 =0.58-0.63) and subcutaneous fat areas (r2 =0.69- 0.71), (p In multivariable linear regression, independent predictors of muscularity (i.e. T4 muscle index) were age (p=0.005), sex (p=0.000), BMI (p=0.000) and HCT-CI (p=0.057). Disease severity (Armand DRI) (p=0.131) was not significantly associated with T4 muscle index. Similar conclusions were obtained for L3 muscle index. In multivariable linear regression adjusted for sex (p=0.000), age (p=0.000) and HCT-CI (p=0.000) and both T4 muscle index (b 0.252 [95%CI 0.126;0.412] p=0.000) and T4 muscle radiodensity (b 0.165 [95%CI 0.110;0.630] p=0.006) were independently associated with FEV1; Armand DRI (p=0.712) and KPS (p=0.991) were not associated with FEV1. Similar conclusions were obtained when muscle index and radiodensity at L3 were considered. Discussion and Conclusion Lumbar or thoracic CT images are useful for body composition assessment in this population, and reveal high rates of sarcopenia, similar to those reported in very elderly patients. Reduced muscle mass and radiodensity associate with impaired FEV1. More muscular patients were male, younger, of high BMI and had fewer comorbidities.