Background: Direct oral anticoagulants (DOACs) are not recommended for venous thromboembolism (VTE) treatment in patients with cancer because their safety and efficacy have not been compared to low molecular weight heparin (LMWH) in large trials. Routine anti-Xa monitoring in cancer patients on LMWH is also not recommended due to limited data correlating anti-Xa levels and outcomes.
Objective: Compare the safety and efficacy of DOACs to LMWH and warfarin and assess the relationship of anti-Xa monitoring and outcomes in patients with cancer taking LMWH in an urban university setting.
Methods: This retrospective, cohort study analyzed the recurrence of VTE and number of bleeding events in patients with cancer.
Results: There were 131 patients included in the analysis. There was no difference seen in the rate of recurrent VTEs between the LMWH, warfarin and DOAC groups (9.3%, 5.9%, 9.1%, p = 0.89). There was also no difference in the rate of bleeding between groups (10.5%, 14.7%, 9.1%, p = 0.576). There was an increased rate of mortality seen in the LMWH group (26.7% vs. 2.9% vs. 18.2%, p = 0.006). There was no difference seen in recurrent VTE (10.3% vs. 8.5%, p = 0.53) or bleeding (10.3% vs. 10.7%, p = 0.661) between the monitored and unmonitored LMWH patients.
Conclusion: Results of this analysis suggest DOACs may be as safe and effective as LMWH and warfarin for the treatment of VTE in patients with cancer, and there may be no clinical benefit to routine anti-Xa monitoring in patients on LMWH treatment. However, larger studies are needed to confirm these observations.
Keywords: Cancer; anti-Xa monitoring; direct oral anticoagulants; low molecular weight heparins; warfarin.