The role of low-molecular-weight heparins in the prevention and treatment of venous thromboembolism in cancer patients.

Accumulating evidence suggests that low-molecular-weight heparins are the drug of choice for the prevention and treatment of venous thromboembolism in patients with cancer. For prophylaxis in the surgical setting, once-daily subcutaneous injections of low-molecular-weight heparin are as effective and safe as multiple doses of unfractionated heparin. Extending prophylaxis with low-molecular-weight heparins beyond hospitalization was recently found to reduce safely the risk of postoperative thrombosis after abdominal surgery for cancer. For the long-term treatment of deep vein thrombosis and in select patients with pulmonary embolism, recently completed clinical trials have shown that secondary prophylaxis with low-molecular-weight heparin is feasible and more effective than oral anticoagulant therapy in preventing recurrent venous thromboembolism in cancer patients. There is also evidence that low-molecular-weight heparins are effective in cancer patients who develop recurrent thrombosis while on warfarin therapy. Lastly, the potential antineoplastic effects of low-molecular-weight heparins make these agents an attractive option in patients with cancer. Although the management of cancer patients with venous thromboembolism remains challenging, low-molecular-weight heparins have simplified and improved the prevention and treatment of venous thromboembolism in these high-risk patients.