Sarcopenia after induction therapy in childhood acute lymphoblastic leukemia: its clinical significance

Muscle weakness is one of the most serious problems during chemotherapy for childhood hematological malignancies. It may be caused by long-term hospitalization, unfavorable physical conditions, and restricted activities. Although the concept of sarcopenia is becoming widely recognized, especially in geriatric medicine, there have been few reports about sarcopenia in pediatric patients with hematological malignancies. A total of 47 consecutive first-onset acute lymphoblastic leukemia (ALL) patients who underwent induction therapy between January 2011 and September 2016 were investigated. The cross-sectional psoas muscle area (PMA) was measured on computed tomography (CT) images. PMA changes were expressed as the Muscle Loss Index (MLI), which was calculated by dividing the post-treatment PMA by the pre-treatment PMA. In this study, patients with values less than the lowest quartile of MLI were classified into the sarcopenia group, and their basic and clinical factors were compared with those in the non-sarcopenia group. Muscle loss was observed in all patients after induction therapy, and severe adverse events during induction therapy were significantly more common in patients in the sarcopenia group. Furthermore, sarcopenia was found to be an independent prognostic factor for invasive fungal infection (IFI) that occurs after induction therapy. The evaluation of sarcopenia on CT images is easy and useful as a predictor of unfavorable events such as IFI in the treatment of childhood ALL.