VPB0286 - Incidence, Risk Factors, and Outcome of Thrombotic Events in Pediatric Cancer Patients

Background: Thrombosis can occur commonly in children with cancer due to presence of different risk factors.

Aims: We aimed to evaluate the incidence, clinical characteristics, risk factors, and outcomes of patients with cancer and thrombosis and to examine the similarities and differences of thrombotic events in patients with leukemia and solid tumors.

Methods: A retrospective study of cancer patients who were diagnosed and treated between January 1, 2016 and January 1, 2021 was conducted. Data of patients who had thrombosis at diagnosis or in the course of their treatments were analysed.

Results: Thrombosis occurred in 15 out of 366 (4%) cancer patients. The incidence of thrombosis in patients with leukemia was 9.3% (7/75). The most common risk factor was the presence of a port catheter (5/7). The majority of thrombosis were located in the upper venous system. Three patients had intracardiac thrombosis. All thrombotic events resolved completely with low molecular weight heparin (LMWH). Recurrent thrombosis developed in one patient. The incidence of thrombosis in patients with lymphoma and solid tumors was 2.7% (8/291; cancer type: neuroblastoma in 2, Wilms tumor in 2, osteosarcoma in 2, and carcinoma in 1). The location of thrombosis was renal vein, vena cava inferior, jugular vein, portal vein, pulmonary vein, and sagittal sinus. Most patients (6/8) with solid tumors had thrombosis at diagnosis. Port-related thrombosis developed in one patient. No inherited thrombophilic risk factors could be defined. Six patients received LMWH, complete resolution was achieved in all.

Conclusion(s): The incidence of thrombotic events was high in patients with leukemia. More than half of solid tumor patients had thrombosis at diagnosis, while leukemia patients developed thrombosis during chemotherapy and after catheter insertion. This finding indicates that development of thrombosis is mostly associated with the disease itself in solid tumors, while it is mostly related to treatment and/or catheter in leukemia patients.