[Multiple myeloma and venous thrombosis. Which thromboprophylaxis should be given?]

Multiple myeloma is a malignant plasma cells dyscrasia that mainly affects patients older than 65 years. These patients are at a higher risk for venous thromboembolism (VTE) because of cancer status, intrinsic risk factors, and exposure to prothrombotic therapies. The risk for VTE appears higher during the first months of myeloma treatment and decreases over time. Exposure to immunomodulatory drugs (IMIDs) such as thalidomide or lenalidomide in association with high doses of dexamethasone or anthracyclin-based chemotherapy is associated with a four-fold increased risk for VTE. Low-dose aspirin, preventive-dose of low molecular weight heparin (LMWH) or vitamin K antagonists were tested for primary prevention of VTE in myeloma patients receiving chemotherapy. The International Myeloma Working Group (IMWG) suggests stratifying VTE risk to decide which patients should receive VTE prevention. Then, the IMWG suggests giving low-dose aspirin to low VTE risk patients and LMWH or vitamin K antagonists to patients at high risk for VTE. For daily practice, it seems reasonable to start preventive doses of LMWH for 3 to 6 months in ambulatory myeloma patients receiving combined therapy with IMID and in all myeloma patients admitted to hospital.