Increased Toxicity Among Adolescents and Young Adults Compared with Children Hospitalized with Acute Lymphoblastic Leukemia at Children's Hospitals in the United States.

Purpose: Adolescent and young adult (AYA) patients (15-39 years old) with acute lymphoblastic leukemia (ALL) have less favorable outcomes and higher treatment-related mortality as compared with older children with ALL. Minimal data exist regarding how well AYA patients tolerate the intensity of chemotherapy at doses and regimens designed for children, and the toxicities suffered by this population at children's hospitals have not been thoroughly characterized. Methods: Pediatric Health Information Systems database was queried to analyze health care outcomes in pediatric (ages 10-14) and AYA patients (ages 15-39) with ALL hospitalized between January 1999 and December 2014. We extracted relevant ICD-9 data for each patient related to grades 3 or 4 toxicities as outlined by the NCI. Results: A total of 5345 hospital admissions met inclusion criteria, representing 4046 unique patients. Of these admissions, 2195 (41.1%) were in the AYA age group, and the remainder were in the 10-14-year-old group. AYA patients had a significantly higher incidence of intensive care unit stay but no difference in median hospital stay nor mortality. AYA patients had increased toxicities in almost every organ system as compared with older children. Conclusions: In this large multicenter US database study, we found an overall increased number of toxicities among AYA patients with ALL in children's hospitals. Compared with children between the ages of 10 and 15, AYA patients developed disproportionately higher toxicities from drugs commonly used in pediatric protocols for ALL. Prospective studies are needed to assess whether dose modifications for certain chemotherapeutics may improve the toxicity profile and health care burden of AYA patients with ALL treated in children's hospitals.