Skeletal muscle and adipose tissue changes in the first phase of treatment of pediatric solid tumors

Body composition is increasingly recognized as an important factor in cancer outcomes. Use of computed tomography (CT) in cancer care provides the opportunity to accurately quantify whole-body lean and adipose tissues from images at the third lumbar spine. We sought to substantiate the use of routinely captured, single-slice chest CT images at the thoracic level for evaluation of skeletal muscle, residual lean tissue, and adiposity among pediatric solid tumor patients. We performed a retrospective analysis among children who underwent treatment for a solid tumor at Columbia University Irving Medical Center. Skeletal muscle (SM), residual lean tissue (RLT), and adipose tissue cross-sectional areas (cm² ) were analyzed at diagnosis and at first follow-up for disease evaluation (6-14 weeks). Imaging analysis was performed utilizing slice-O-matic image analysis software. Of the 57 patients identified, 39 had chest CT imaging that included intervertebral level T12-L1, and 22 also had concurrent imaging at L3. Correlation coefficients between body composition variables at T12-L1 and L3 were strong (r = 0.93-0.98). Paired t-test showed a significant decrease in SM (-4.2 ± 8.12, p = 0.003) and RLT (-10.7 ± 28.5, p = 0.025) as well as a trend toward a significant increase in visceral adipose tissue (3.10 ± 9.65, p = 0.052). Univariable analysis demonstrated a significant association between increasing age and increased SM loss (β = -0.496 with SE = 0.194, p = 0.011), and a lack of association between body mass index and body composition changes. We provide the first line of evidence that single-slice images from routinely obtained chest CT scans provide a simple, readily available mechanism for assessing body composition in pediatric solid tumor patients. Adverse body composition changes were observed, particularly among adolescents and young adults. Precis: Changes in body composition can be detected via routine CT images in pediatric patients undergoing treatment for solid tumors.