INTRODUCTION:
Children with cancer are at increased risk for venous thrombosis (VT) or
venous thromboembolism (VTE). This complication can manifest as bland
thrombus or tumor thrombus1,2. Tumor thrombus is
defined as the extension of the tumor into the vessel lumen, typically a
vein. Incidence of tumor thrombus varies depending upon the type of
cancer3. In children, it is most widely reported to be
associated with Wilms tumor4,5. Although pathologic
exam is the reference standard, imaging is very reliable and helps in
early detection of tumor thrombus, without the use of any invasive
technique6.
Bland thrombus on the other hand, is a fibrin clot without neoplastic
cells which may occur in patients with or without an underlying
malignancy. Bland thrombus is thought to result from the interaction of
various factors such as cancer type, presence of central venous
catheters, chemotherapy and acquired or inherited prothrombotic defects,
among others1. Cancer can also contribute to the
development of bland thrombus by mechanical effects on the venous flow,
as in those with solid tumors2. It is unknown if
intravascular extension or tumor thrombus increase the risk for bland
thrombus formation. Anticoagulation is sometimes administered in
conjunction with cancer-directed therapy to this group of patients.
Available literature describing the treatment characteristics and
outcomes of pediatric patients with solid tumor-associated tumor
thrombus is limited, and there are no evidence-based studies to guide
management. The purpose of this study is to describe the role of
anticoagulation in patients with tumor thrombus. We performed a
retrospective review at a large pediatric tertiary care center to
evaluate the clinical and treatment characteristics of patients with
tumor thrombus, indications for starting anticoagulation, and rate of
bland tumor formation and bleeding events for those treated with and
without anticoagulation.