Thrombotic disorders

Abstract

Thromboembolism is a well-recognized complication of cancer in children, with important clinical and therapeutic implications. The exact incidence is unknown, with wide variation in reported rates. Thromboembolism has been most extensively studied in acute lymphoblastic leukemia but also affects children with other malignancies. Risk factors include the presence or dysfunction of a central venous catheter, inherited thrombophilia, use of asparaginase and steroids, older age, and intrathoracic or metastatic disease. The most commonly affected sites are the central nervous system in acute lymphoblastic leukemia and the upper extremity veins which are often associated with a central venous catheter. Current evidence does not support screening asymptomatic patients or providing routine prophylactic anticoagulation in pediatric cancer patients. For patients with symptomatic thromboembolism, a review of the evidence for different therapeutic anticoagulation modalities is discussed with graded recommendations; due to a lack of reported data, much of the guidelines are based on expert opinion or consensus statements. The necessary duration of therapy is unknown but generally depends on clinical response and the presence of ongoing risk factors for bleeding or thrombosis. Additional research is needed to better understand the epidemiology of throm bosis in childhood cancer and to optimize both therapy and prevention.