Newer Insights on the Occurrence of Sarcopenia in Pediatric Patients with Cancer: A Systematic Review of the Past 5 Years of Literature.

BACKGROUND/OBJECTIVES: Sarcopenia, defined as the progressive loss of muscle mass and function, is increasingly recognized in pediatric cancer patients as a significant clinical and prognostic factor. Sarcopenia in children arises from malignancy-related inflammation, malnutrition, and treatment toxicity, negatively affecting treatment response, recovery, and quality of life. METHODS: We searched MEDLINE and Scopus for English-written articles published over the last five years using synonyms for the terms "sarcopenia" and "pediatric cancer". Screening and data extraction were performed in a duplicate-blinded method. We qualitatively synthesized eligible articles. RESULTS: Recent studies identify pre-treatment sarcopenia as a marker of poor prognosis, especially in hepatoblastoma and neuroblastoma. Total psoas muscle area (tax) and skeletal muscle index (SMI) are emerging diagnostic tools, though standardized methods remain lacking. Sarcopenia's etiology is multifactorial, involving impaired mitochondrial metabolism, chemotherapy-induced appetite loss, and systemic inflammation. Sarcopenic obesity is common, particularly among leukemia survivors, often masked by normal BMI. Survivors also face reduced bone density, impaired immunity, and persistent muscle loss, linked to prior therapies such as radiotherapy and hematopoietic stem cell transplantation. Increase in muscle mass post-treatment correlates with better survival outcomes. CONCLUSIONS: Early detection of sarcopenia can support timely interventions such as nutritional support and physical activity. Yet, significant diagnostic heterogeneity across existing studies hampers definitive conclusions regarding its true prevalence and the optimal assessment method. Standardized diagnostic criteria are urgently needed to enable more reliable prevalence estimates and evidence-based clinical strategies.