Prognostic impact of sarcopenia in children with cancer: a focus on the psoas muscle area (PMA) imaging in the clinical practice.

Skeletal muscle plays a crucial part in the metabolic and inflammatory response. "Sarcopenia", defined as a pathological condition of reduced strength, quantity and quality of skeletal muscle mass, may often develop in the young age as the secondary consequence of a systemic inflammatory illness, like cancer. In children with cancer, sarcopenia is a common finding, playing a negative role in their prognosis. However, its prevalence in clinical practice is underestimated. Moreover, several pre- and post-natal factors may influence skeletal muscle development in childhood, making the issue more complex. Given the frequent use of radiological imaging in clinical practice, prompt analysis of body composition is feasible and able to detect the presence of reduced fat-free mass (FFM) among pediatric patients with cancer. We discuss the recent advances in the study of body composition in children with cancer, dissecting the role of the psoas muscle area (PMA) measure, obtained from computerized tomography (CT) or magnetic resonance images (MRI) as a marker of sarcopenia in this setting. Since age and sex-specific percentile curves for PMA and a PMA z-scores calculator are available online, such a tool may be useful to simply detect and treat sarcopenia and its consequences in childhood cancer.