prevention of recurrent VTE in cancer patients
- related: Oncology
- tags: #hemeonc #pulmonary
Links to this note
- low molecular weight heparin is first line treatment
- edoxaban, apixaban, rivaroxaban are noninferior
- warfarin is less effective
Patients with cancer have a 4-7 fold increased risk of venous thromboembolism (VTE). Long-term VTE treatment is different in cancer patients than patients without cancer. Low molecular weight heparin (LMWH) is more effective than vitamin K antagonists (e.g., warfarin) in reducing the risk of recurrent VTE in cancer patients (while on therapy), and they do not significantly increase the risk of bleeding. However, LMWH is not associated with improved survival in these patients.
Though more effective, other factors must be taken into consideration when prescribing LMWH, such as patient preference (e.g., needle vs. pills), comorbidities (e.g., renal insufficiency), and cost (e.g., copays).
VTE is a substantial cause of morbidity and mortality in patients with malignancy and in some series is the second most common cause of death, behind only the underlying malignancy itself. Data suggest that apixaban provides protection from recurrent events that is noninferior to a low-molecular-weight heparin (believed to be the most efficacious agents in this setting) without an increase in bleeding events and without the discomfort and lower adherence associated with an indefinite injectable therapy (choice A is correct). Notably, studies with other direct oral anticoagulants have shown variable efficacy and safety, but overall they are less established than apixaban in this setting. As examples, both edoxaban and rivaroxaban have shown increased rates of bleeding vs low-molecular-weight heparin in some studies, particularly in the setting of GI cancers.
Warfarin is not considered a first-line agent in the treatment of malignancy-associated VTE because of studies that have shown lower efficacy for warfarin than low-molecular-weight heparin (choice D is incorrect). Aspirin is inadequate therapy for VTE in patients with and without malignancy (choice B is incorrect.)
Inferior vena cava filter placement is reserved for patients either who cannot be administered anticoagulants because of safety concerns or who develop recurrent VTE despite therapeutic anticoagulation (choice C is incorrect).
Notably, while the duration of therapy in patients with VTE who have reversible or transient risk factors is usually 3 to 6 months, patients with active cancer are generally treated for longer periods, frequently indefinitely. For this purpose, active cancer is defined by the International Society on Thrombosis and Haemostasis as:
- Cancer diagnosed in the previous 6 months;
- Recurrent, regionally advanced, or metastatic cancer;
- Cancers for which treatment has been administered within 6 months;
- Hematologic malignancies in which complete remission has not been obtained.1