A Comparison of Extremity Thrombosis Rates in Adolescent and Young Adult Versus Younger Pediatric Oncology Patients at a Children's Hospital.

Purpose: To examine whether the rates of thrombosis in children (≤14 years of age) and adolescent/young adult (AYA) patients (15-22 years of age) with cancer is different.

Methods: We retrospectively studied the rates of thrombosis in children and AYA patients at the Children's Hospital of Pittsburgh during the years 2002-2010, using the tumor registry database. This list was then divided into two groups based on age at diagnosis. A review of ICD-9 codes from hospital billing records was then performed to identify patients who carried diagnoses of cancer (140.x-239.x) and venous thrombosis of the extremities/vena cavae (453.x) simultaneously. This list was confirmed by electronic medical record review. Proportions, comparisons, and descriptive statistics were then performed.

Results: One thousand three hundred nine total patients were identified; 274 patients fit into the AYA age category (mean age 17.3 years) and 1036 patients were in the child group (mean age 6.5 years). Overall, 30 patients (2.29%) had thrombosis: 4.76% of the AYA patients (13/273) and 1.64% of the child group (17/1036). The difference in these proportions had a p-value = 0.004.

Conclusions: This study suggests that the risk of extremity deep vein thrombosis is higher in the AYA subset of oncology patients than in the patients who are 14 years or younger. Prospective studies to elucidate the true rate of thrombosis, as well as to study the benefit of prophylactic anticoagulation in the AYA population, should be undertaken.