OBJECTIVES: Despite progress in the treatment of childhood acute lymphoblastic leukemia, severe complications are common, and the need of supportive care is high. We explored the cumulative prevalence, clinical risk factors, and outcomes of children with acute lymphoblastic leukemia, on first-line leukemia treatment in the ICUs in Sweden.

DESIGN: A nationwide prospective register and retrospective chart review study.

SETTING: Children with acute lymphoblastic leukemia were identified, and demographic and clinical data were obtained from the Swedish Childhood Cancer Registry. Data on intensive care were collected from the Swedish Intensive Care Registry. Data on patients with registered ICU admission in the Swedish Childhood Cancer Registry were supplemented through questionnaires to the pediatric oncology centers.

PATIENTS: All 637 children 0-17.9 years old with acute lymphoblastic leukemia diagnosed between June 2008 and December 2016 in Sweden were included.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Twenty-eight percent of the children (178/637) were admitted to an ICU at least once. The Swedish Intensive Care Registry data were available for 96% of admissions (241/252). An ICU admission was associated with poor overall survival (hazard ratio, 3.25; 95% CI, 1.97-5.36; p <= 0.0001). ICU admissions occurred often during early treatment; 48% (85/178) were admitted to the ICU before the end of the first month of acute lymphoblastic leukemia treatment (induction therapy). Children with T-cell acute lymphoblastic leukemia or CNS leukemia had a higher risk of being admitted to the ICU in multivariable analyses, both for early admissions before the end of induction therapy and for all admissions during the study period.

CONCLUSIONS: The need for intensive care in children with acute lymphoblastic leukemia, especially for children with T cell acute lymphoblastic leukemia and CNS leukemia, is high with most admissions occurring during early treatment.