Venous thromboembolism prophylaxis in patients with multiple myeloma: where are we and where are we going?

Venous thromboembolism is a common complication of patients with hematologic malignancies, due both to release of procoagulant factors by tumor cells and to external factors, such us drugs. In multiple myeloma patients, the risk is increased by use of immunomodulants, especially when associated to multidrug therapy, during the induction phase. Prevention of venous thromboembolism in myeloma patients is highly recommended but specific guidelines are still lacking. The most common approach is to stratify the thrombotic risk according to individual, myeloma-related and therapy-related risk factors and to use aspirin for all patients, except those with two or more thrombotic risk factors who should be treated with traditional oral or parenteral anticoagulant. A more controversial approach indicates for prophylaxis either anticoagulant or aspirin, regardless of risk stratification. Recent trials investigate prophylaxis in myeloma patients with direct oral anticoagulants, based on studies showing efficacy and safety of this new class of drugs in the treatment and prophylaxis of thrombosis in patients with any malignancy. The results of these trials are encouraging but they need to be confirmed by larger studies. An international consensus about best prophylaxis to prevent venous thromboembolism in patients with multiple myeloma on treatment is still missing. Therefore, thrombosis in multiple myeloma remains an ongoing issue.