Written by Peter Liu
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Extending the duration of anticoagulation for patients with malignancy-associated PE decreases the risk of recurrent VTE.
Treating VTE should also prevent recurrence when risk is high
In this Japanese RCT of patients with low-risk, malignancy-associated pulmonary embolism (PE), rivaroxaban therapy for 18 months compared to 6 months resulted in a 75% lower likelihood of developing recurrent venous thromboembolism (VTE; OR 0.25, 95%CI 0.09-0.72, p=0.01), with a non-significant increased risk of bleeding (OR 1.43, 0.44-4.70, p=0.55). This suggests most patients with malignancy-associated PE should be on extended anticoagulation durations. If we utilize the framework for VTE treatment proposed by the American Society of Hematology (ASH) 2020 guidelines, the 18-month duration used in the RCT feels arbitrary. ASH suggests that VTE treatment should consist of 3-6 months of acute treatment, followed by a decision regarding prolonged secondary prevention of recurrent VTE. In this framework, patients with high risk for VTE recurrence and acceptable bleeding risk should continue anticoagulant (AC) therapy for secondary prevention indefinitely, until clinical circumstances change the risk/benefit balance. Patients with active malignancy such as those in this RCT generally fit into this category, so the results of this RCT seem natural. An approach which may be even more sophisticated could be reduced-dose AC dosing during the secondary prevention phase, though patients with malignancy-associated VTE were poorly represented in most of the studies of reduced-dose AC (e.g. NEJM 2013 for reduced-dose apixaban).
How will this change my practice?
For patients that have VTE associated with active cancer, especially those with history of PE, I would strongly consider extending AC therapy for secondary prevention of VTE recurrence for as long as the cancer remains active and bleeding risks are acceptable.
Source
Rivaroxaban for 18 Months Versus 6 Months in Patients With Cancer and Acute Low-Risk Pulmonary Embolism: An Open-Label, Multicenter, Randomized Clinical Trial (ONCO PE Trial). Circulation. 2024 Nov 18. doi: 10.1161/CIRCULATIONAHA.124.072758. Epub ahead of print. PMID: 39556015
