Managing the competing risks of thrombosis, bleeding, and anticoagulation in patients with malignancy

The association between malignancy and thrombosis has been recognized for over a century and a half. Patients with cancer have an elevated risk of both initial and recurrent venous thromboembolism (VTE) compared with patients without cancer owing to cancer- and patient-specific factors. Recurrent VTE is common despite anticoagulation, presenting additional management challenges. Patients with cancer also have an increased risk of bleeding when on anticoagulants compared with patients without cancer. This bleeding risk is heightened by the thrombocytopenia common in patients with hematologic malignancies and those treated with intensive myelosuppressive chemotherapy regimens. Despite the advancements in cancer-directed therapy made over the past 15 years, numerous large studies have confirmed that bleeding and VTE recurrence rates remain high in cancer patients. Balancing the increased and competing risks of clotting and bleeding in these patients can be difficult, because management of cancer-associated thrombosis requires anticoagulation despite known increased risks for bleeding. In the context of challenging illustrative cases, this review will describe management approaches to clinical scenarios in which data are sparse: cancer patients with recurrent VTE despite anticoagulation and cancer patients with a new VTE in the setting of severe thrombocytopenia.