PURPOSE: To examine longitudinal changes in trunk muscle mass during chemotherapy in children and adolescents with lower-limb osteosarcoma and to compare these changes according to surgical procedure. METHODS: abdominal analysis system. Changes in trunk muscle mass from admission to discharge were categorized as increase (≥5%), maintenance (±5%), or decrease (≤-5%). Rehabilitation-related variables and surgical procedures were examined in relation to muscle mass changes. RESULTS: The mean age was 13.7 years (eight males and three females). Seven patients underwent limb-sparing surgery, and four underwent amputation. No significant associations were observed between rehabilitation-related variables (hospitalization duration, rehabilitation frequency, or session duration) and trunk muscle mass changes. However, a significant association was identified between surgical procedure and trunk muscle mass changes. All patients who underwent amputation maintained or increased muscle mass, whereas five of the seven patients who underwent limb-sparing surgery experienced a decrease. CONCLUSION: In this retrospective observational study, trunk muscle mass changes during chemotherapy were associated with the type of surgical procedure but not with rehabilitation-related variables. Further studies with larger sample sizes are warranted to better understand factors associated with muscle mass changes in this population.
Aoki et al. (2026) studied this question.