Deep vein thrombosis in cancer: the scale of the problem and approaches to management.

Patients with cancer have long been recognised to be at high risk of venous thromboembolism (VTE), although the condition remains under diagnosed and under treated in these patients. As a consequence, the morbidity and mortality due to deep venous thrombosis and pulmonary embolism remains unacceptably high in this group. Furthermore, the management of VTE in the presence of malignancy is complex, due both to the effects of the cancer itself and its treatments. Conventional long-term management of VTE involves the use of vitamin K antagonists (VKAs), such as warfarin, to reduce the risk of recurrence. However, this approach is associated with a range of practical difficulties including the need for regular laboratory monitoring, the potential for drug interactions, in addition to the risk of treatment resistance and bleeding in patients with cancer. Recent research indicates that the use of low molecular weight heparin (LMWH) therapy instead of VKAs may be beneficial in these patients. In particular, evidence from a large clinical trial of the LMWH dalteparin indicates that this agent offers an effective alternative to VKAs in the long-term management of VTE, that is free from the practical problems associated with the use of VKAs and without increasing the risk of bleeding.