In patients with cancer, the introduction of direct oral anticoagulants (DOACs) is an important milestone for improving care. However, use of these drugs in certain oncology populations can result in poor outcomes, and a thorough understanding of the evidence is necessary to maximize benefit and minimize harm. Monotherapy with low-molecular-weight heparin (LMWH) is more efficacious than vitamin K antagonist (VKA) therapy for treatment of cancer-associated thrombosis, and it remains a reliable and experience-proven therapy. Its main limitations are the cost and inconvenience of daily subcutaneous injections but its major advantages include ease of dose titration, lack of drug-drug interactions (DDIs), and good tolerance in those with gastrointestinal (GI) toxicity or mucosal abnormalities. Evidence to date demonstrates that some DOACs have similar or better efficacy but higher risk of clinically significant bleeding compared with LMWH. The bleeding risk is particularly high in those with GI malignancies, and bleeding occurs most commonly in the upper GI tract. DDI is another concern for DOACs, especially with the polypharmacy and changing anticancer therapies that characterize the journey of many patients living with cancer. However, given the cost of DOACs, VKA therapy is still frequently used, and so clinicians need to remain skilled in VKA dose adjustment and monitoring. Like DOACs, performance of VKA is unpredictable in those with nausea and vomiting, mucositis, and inflammatory colitis but is even more sensitive to DDI. DOAC is a welcomed addition to help clinicians individualize anticoagulant therapy in cancer patients with thrombosis.

Correspondence: Agnes Y. Y. Lee, Diamond Health Care Centre, 2775 Laurel St, 10th Floor, Vancouver, BC V5Z 1M9, Canada; e-mail: alee14@bccancer.bc.ca.

Author notes

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Contribution: A.Y.Y.L. reviewed the literature, analyzed the data, and wrote the manuscript.

Competing Interests

Conflict-of-interest disclosure: A.Y.Y.L. has received research funding support from Bristol-Myers Squibb; honoraria for consultancy from Bayer, Bristol-Myers Squibb, LEO Pharma, and Pfizer; and is a member of clinical practice guideline panels or has made guidance documents for the American Society of Hematology, the American Society of Clinical Oncology, the International Society on Thrombosis and Haemostasis, and Medical Services Comission, British Columbia, Canada.

Supplemental data