**8. Treatment of VTE**

Treatment for VTE has been widely studied, and treatment guidelines have been published and frequently updated by the American College of Chest Physicians (ACCP), American College of Emergency Physicians, Eastern Association for the Surgery of Trauma, and Institute for Clinical Systems Improvement(1,3). Generally, acute treatment consists of lowmolecular-weight heparin (LMWH) or unfractionated heparin (UFH) for 4 to 5 days, with overlapping therapy to warfarin until an international normalized ratio (INR) of >2 for two consecutive days is achieved. Anticoagulation should be continued for at least 3 to 12 months, depending on the site of thrombosis and risk factors. Failure to provide adequate VTE treatment can result in patient morbidity and mortality, with a substantial economic burden(73). Although the evidence and consensus strongly favor LMWH treatment for up to 6 months in patients with cancer with established VTE, evidence is lacking to support continuing treatment beyond 6 months. It is likely that anticoagulation can be safely discontinued in certain patients (eg, patients who developed a VTE while on adjuvant chemotherapy and are in complete remission withnoplans for further treatment). Conversely, certain patients will continue to be at risk for recurrent VTE (eg, a patient with cancer with metastatic disease with plans for indefinite chemotherapy). Data from welldesigned randomized clinical trials are essential for clinicians to make evidencebased recommendations in these varied settings.

Activation of the hemostatic system promotes tumor growth, angiogenesis, and metastasis. Antithrombotic agents could therefore potentially influence tumor biology and outcomes in patients with cancer. Multiple recent studies have evaluated the effect of anticoagulants on survival, with encouraging but inconclusive results (74). Given that anticoagulant prophylaxis could have dual benefits for patients with cancer reducing VTE and prolonging survival it is vital to pursue well-designed clinical trials of thromboprophylaxis focusing on survival(75).
