Other agents: Fondaparinux is a factor Xa inhibitor rarely associated with heparin-induced thrombocytopenia (HIT), which makes it an attractive alternate anticoagulant for HIT patients. Its use in comparison with other parenteral anticoagulants has not been established in patients with malignancy.
Fondaparinux is FDA-approved for initial VTE treatment, and is used in practice as an alternative prophylactic anticoagulant for patients with HIT history or heparin allergy.7 However, no randomized clinical trials have evaluated its efficacy in patients with HIT.
Several new oral anticoagulants, including direct thrombin and factor Xa inhibitors, are being investigated; efficacy has not been established in cancer patients.7
Inferior vena cava (IVC) filters: Limited data surround the use of IVC filters, and most consensus guidelines recommend their use only in specific settings. One randomized controlled study (not limited to patients with cancer) showed no difference in overall short-term or long-term survival among patients receiving IVC filters for VTE treatment. However, there was a decrease in symptomatic PE in the filter group 12 days after placement. The tradeoff was significantly more recurrent DVTs at two years’ followup. The authors concluded that systematic use of IVC filters is not recommended.14
Because all of the study participants in this trial were receiving concomitant anticoagulation, it is difficult to generalize results to patients who have contraindications to anticoagulation. Nonetheless, ASCO, NCCN, and several other guideline panels recommend IVC filters only for patients with contraindications to anticoagulation or failure of long-term anticoagulation. NCCN broadens these recommendations for IVC filter placement to include patients with severe cardiac or pulmonary dysfunction.6 However, this recommendation is controversial, given the lack of supporting data, cost, and invasiveness of the procedure.7
All patients with IVC filters without contraindication to anticoagulation should be anticoagulated.9
Prophylaxis: The importance of VTE prophylaxis in all hospitalized patients, including patients with cancer, is under close scrutiny in an attempt to improve patient safety and quality. The Centers for Medicare & Medicaid Services (CMS), in conjunction with the Joint Commission, has added VTE to its list of conditions that are reasonably preventable, and hospitals will no longer be reimbursed for the cost of treatment if acquired during a hospital stay. This rule currently is in effect for knee and hip replacements.15
The need for improvement in aggressive and appropriate prophylaxis of hospitalized patients was demonstrated by a single study in which just one-third of hospitalized patients received appropriate prophylaxis, according to American College of Chest Physicians (ACCP) guidelines.16
Despite a lack of robust data regarding VTE prophylaxis in patients with malignancy, strong data exist for VTE prophylaxis in hospitalized patients. All patients with cancer, and without contraindications to anticoagulation, should receive pharmacologic VTE prophylaxis while hospitalized. In the absence of supporting data, guidelines do not suggest VTE prophylaxis for ambulatory patients with cancer, except in certain multiple myeloma patients.6
Intracranial malignancies: Patients with intracranial malignancies are at risk for VTE, and the presence of intracranial tumors or metastases are not absolute contraindications to anticoagulation. However, data are sparse regarding VTE therapy in this subgroup. Active intracranial bleeding is an absolute contraindication to anticoagulation, and it should be avoided in patients with recent intracranial surgery or thrombocytopenia (e.g., platelet count < 50 x 109).4 In general, the presence of intracranial lesions without high-risk features should not deter the use of prophylactic anticoagulation.
Thrombocytopenia: Cancer patients frequently have chemotherapy-induced cytopenias, including thrombocytopenia. There is a paucity of data regarding anticoagulation in the setting of thrombocytopenia. In a recent review of VTE in the setting of cancer, Lee suggests dose reduction of LMWH by half in patients with platelet counts between 20 and 50 x 109/L.7 At our institution, hematologists suggest halving treatment-dose LMWH at platelet counts between 30 and 50 x 109/L, and discontinuing pharmacologic prophylaxis at platelet counts of less than 50 x 109/L—although there are little data to support these recommendations. Anticoagulation should be discontinued in patients with platelet counts below 20-30 x 109/L, as the risk of bleeding becomes too high.7