Evolution of heparin anticoagulants to ultra-low-molecular-weight heparins: A review of pharmacologic and clinical differences and applications in patients with cancer

The burden of venous thromboembolism (VTE) is high in patients with cancer, particularly those with metastatic disease and those receiving chemotherapy. The use of heparin and heparin derivatives should be considered for primary prevention of VTE in hospitalized patients with cancer and in patients undergoing cancer surgery. Preliminary evidence also suggests that heparins may have direct anticancer benefits owing to effects on tumor growth, angiogenesis, and metastasis. Despite the potential benefits of heparin-derived anticoagulants, many at-risk patients do not receive adequate thromboprophylaxis. The evolution of unfractionated heparin to low-molecular-weight and ultra-low-molecular-weight heparins has provided practitioners with alternatives for VTE prevention in cancer, although these alternatives present challenges related to clinically relevant pharmacologic differences between agents. In this review, we present results from our review of the medical literature focusing on the use of the heparin-derived anticoagulants in prospective interventional studies of primary thromboprophylaxis in patients with cancer in surgical, hospitalized, and ambulatory settings.