Treatment of Venous Thromboembolism in Cancer. Historical Perspective and Evolving Role of the Direct Oral Anticoagulants.

The management of cancer-associated thrombosis (CAT) is complex, and treatment strategies have been evolving over the past 15 years. It is well recognized that oral vitamin K antagonists are difficult to use in cancer patients, with higher rates of treatment failure and bleeding complications than in non-cancer patients. Low-molecular-weight-heparin (LMWH) became the widely accepted standard of care for treatment of cancer-associated thrombosis, following the CLOT study comparing dalteparin with warfarin in 2003. LMWH remains widely used for the treatment of CAT. However, in the past two years, several studies have served to validate direct oral anticoagulants as a safe and effective alternative to LMWH. Two randomized clinical trials comparing edoxaban and rivaroxaban with dalteparin, and several retrospective studies have shown the efficacy of edoxaban and rivaroxaban for the treatment of CAT. However, there is an evidence of increased bleeding with the DOACs, particularly gastrointestinal or urinary tract bleeding in patients with lesions within the gastrointestinal or urinary tracts. This chapter discusses the ongoing development of optimal treatment strategies for cancer-associated thrombosis.