Prospective study of thromboembolism in 1038 children with acute lymphoblastic leukemia: a Nordic Society of Pediatric Hematology and Oncology (NOPHO) study

J Thromb Haemost. 2016 Mar;14(3):485-94. doi: 10.1111/jth.13236. Epub 2016 Jan 30.

Abstract

ESSENTIALS: Children with acute lymphoblastic leukemia (ALL) are at risk of thromboembolism (TE). This is a prospective evaluation of the incidence, risk factors and outcomes of TE in 1038 children with ALL. TE occurred in 6.1% of children, with the highest incidence (20.5%) among those aged 15-17 years. A TE-associated case fatality of 6.4% indicates that TE is a severe complication of ALL treatment.

Background: Thromboembolism (TE) is a major toxicity in children with acute lymphoblastic leukemia (ALL) and may have a negative impact on ALL treatment.

Objectives: To examine the cumulative incidence, outcomes and risk factors associated with TE in children with leukemia.

Patients/methods: We prospectively evaluated TE in 1038 Nordic children and adolescents (≥ 1 and < 18 years) diagnosed with ALL during 2008-2013 and treated according to the NOPHO (Nordic Society of Pediatric Hematology and Oncology)-ALL 2008 protocol. The cohort was followed until December 2014. Cox proportional regression was used to compute hazard ratios (HRs).

Results: TE events (n = 63) occurred most frequently in conjunction with asparaginase (ASP) administration (52/63). The cumulative incidence of TE was 6.1% (95% confidence interval [CI], 4.8-7.7). Being aged 15-17 years was associated with an increased risk of TE (adjusted HR of 4.0; 95% CI, 2.1-7.7). We found a TE-associated 30-day case fatality of 6.4% (95% CI, 1.8-15.5) and TE-related truncation of ASP therapy in 36.2% (21/58). Major hemorrhage occurred in 3.5% (2/58) of anticoagulated patients. Minor hemorrhage was reported in two out of 58 patients. No major bleeds occurred in children who received low-molecular-weight heparin.

Conclusions: Methods to identify children and adolescents who will benefit from thromboprophylaxis during ALL treatment are called for. The truncation of ASP should be avoided. The long-term survival outcomes for ALL patients with TE require close monitoring in the future.

Keywords: acute lymphoblastic leukemia; asparaginase; children; thromboembolism.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Age Distribution
  • Anticoagulants / adverse effects
  • Antineoplastic Agents / adverse effects
  • Asparaginase / adverse effects
  • Child
  • Child, Preschool
  • Estonia / epidemiology
  • Female
  • Hemorrhage / chemically induced
  • Hemorrhage / epidemiology
  • Humans
  • Incidence
  • Infant
  • Lithuania / epidemiology
  • Male
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / diagnosis
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / drug therapy
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / epidemiology*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / mortality
  • Proportional Hazards Models
  • Prospective Studies
  • Risk Factors
  • Scandinavian and Nordic Countries / epidemiology
  • Thromboembolism / diagnosis
  • Thromboembolism / epidemiology*
  • Thromboembolism / mortality
  • Thromboembolism / prevention & control
  • Time Factors
  • Treatment Outcome

Substances

  • Anticoagulants
  • Antineoplastic Agents
  • Asparaginase