Treatment and secondary prevention of venous thromboembolism in cancer

Patients with cancer who develop venous thromboembolism (VTE) are at elevated risk for recurrent thrombotic events, even during anticoagulant therapy. The clinical picture is further complicated because these patients are also at increased risk of bleeding while on anticoagulants. In general, there are four key goals of treatment for VTE: preventing fatal pulmonary embolism (PE); reducing short-term morbidities associated with acute leg or lung thrombus; preventing recurrent VTE; and preventing the long-term sequelae of VTE (e.g., post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension). A fifth goal – minimising the risk for bleeding while on anticoagulation – is particularly warranted in patients with cancer. Traditionally, pharmacological treatment of VTE has two phases, with the transition between phases marked by a switch from a rapid-acting, parenterally administered anticoagulant (such as unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), or fondaparinux) to an oral vitamin K antagonist (e.g., warfarin). Recent clinical trials of established agents and the advent of new pharmacological options are changing this paradigm. Low-molecular-weight heparin continued for 6 months is more effective than warfarin in the secondary prevention of VTE in cancer patients without increasing the risk of bleeding and is now the preferred treatment option. Given the impact of VTE on short-term and long-term outcomes in patients with cancer, a group of health-care providers based in the United Kingdom gathered in London in 2009 to discuss recent data on cancer-associated thrombosis and to evaluate how these recommendations can be integrated or translated into UK clinical practice. This article, which is the third of four articles covering key topics in cancer thrombosis, focuses on treatment and secondary prevention of VTE in cancer patients.