Body composition and treatment-related toxicity in pediatric lymphoma.

Abstract

e22503 Background: Body composition is an emerging predictor of toxicity and survival in older adults with cancer ( Shachar, Eur J Can, 2016); however, its role in pediatric cancer is not known. We examined body composition (using computed-tomography [CT] scans at the 3rd lumbar level) in children with lymphoma (Hodgkin [HL] and non-Hodgkin [NHL]) at cancer diagnosis and examined its association with treatment-related toxicities. Methods: We constructed a retrospective cohort of 87 consecutive children (HL: n = 45; NHL: n = 42) diagnosed between 2000 and 2015 (2-21y at diagnosis) with pretreatment abdominal CT scans. Body composition was assessed using sliceOmatic (TomoVision) and included skeletal muscle index (SMI, cm2/m2), skeletal muscle density (SMD: Hounsfield units [HU]), and height-adjusted total adipose tissue (hTAT: sum of visceral, intramuscular and subcutaneous adipose tissue, cm2/m2). For the analysis, we used skeletal muscle gauge (SMG = SMI x SMD, expressed per 1000 in arbitrary units [AU]) and hTAT. Sociodemographics, disease and treatment details, as well as toxicities (CTCAE v5) were abstracted from medical records. Proportion of chemotherapy cycles with grade 4 hematologic or grade 3-4 non-hematologic toxicities were calculated (percent toxicity). Generalized linear regression models were constructed to examine associations between body composition metrics and toxicities, adjusting for age at diagnosis, gender, race/ethnicity and lymphoma subtype. Results: Median age at diagnosis was 12.9y (range, 2-18.5y); 60.9% males; 60.4% non-Hispanic white. Median BMI%ile was 62 (0-99), median SMG was 2.2AU (0.9-3.7) and median hTAT was 20.1 cm2/m2 (0.04-226.7). Overall, the mean percent toxicity for grade 4 hematologic and grade 3-4 non-hematologic toxicity was 38.9% (±32.6) and 31.4% (±32.6) respectively. Correlation was poor between SMG and BMI%ile ( R2= 0.04), SMG and hTAT ( R2= -0.01) and moderate between hTAT and BMI%ile ( R2= 0.4). SMG was significantly associated with grade 4 hematologic percent toxicity ( β= -18, P= 0.007) after adjusting for hTAT and cancer type. BMI%ile was not associated with grade 4 hematologic percent toxicity ( β= -0.09, P= 0.5). Non-hematologic percent toxicity was not associated with BMI%ile, hTAT or SMG. Conclusions: In this first study of its kind, we find that children with poorer muscle quality are more likely to experience grade 4 hematologic toxicities. These findings form the basis for larger studies to incorporate body composition when developing prediction models for chemotherapy-related toxicity and disease outcomes.