Exploring Pain and Body Composition in Children with Cancer Compared to Healthy Controls: A Cross-Sectional Case-Control Study

<b>Background:</b> Children with cancer frequently experience pain, which may persist into survivorship. Furthermore, many undergo body composition changes throughout their disease trajectory. However, little is still known about the interplay between pain and body composition. <b>Methods:</b> This cross-sectional case-control study compared pain and anthropometric characteristics between 30 children with cancer (8-18 years) and 30 age- and sex-matched healthy controls and examined whether pain was associated with anthropometric characteristics and cancer diagnosis. Pain in the past two weeks, chronic pain, and pressure pain thresholds (PPTs) at the tibialis anterior and trapezius pars descendens muscles were assessed. Anthropometric measures included waist circumference, fat %, fat-free mass, muscle mass, body water %, and Body Mass Index. <b>Results</b>: Children with cancer had a higher prevalence of chronic pain (<i>p</i> = 0.011), lower PPTs at the tibialis anterior (<i>p</i> = 0.030), and fewer pain locations (<i>p</i> = 0.037). They also showed lower body water % (<i>p</i> = 0.020), and higher waist circumference (<i>p</i> = 0.012) and fat % (<i>p</i> = 0.026). Cancer diagnosis and lower muscle mass were associated with lower PPTs at both locations (tibialis anterior: <i>p</i> = 0.016, β = -0.305; <i>p</i> = 0.033, β = 0.267; trapezius pars descendens: <i>p</i> = 0.020, β = -0.286; <i>p</i> = 0.004, β = 0.361, respectively). <b>Conclusions:</b> Children with cancer differ from their healthy peers in both pain and body composition profiles. These findings underscore the need for systematic pain assessment and body composition monitoring in pediatric oncology and may help identify children at risk for heightened pain sensitivity and adverse body composition changes who could benefit from early, targeted interventions.