Direct oral anticoagulants compared to low-molecular-weight heparin for the treatment of cancer-associated thrombosis: Updated systematic review and meta-analysis of randomized controlled trials

Background: Low-molecular-weight-heparins (LMWHs) have been established for the treatment of cancer-associated venous thromboembolism (VTE). Recently published randomized controlled trials (RCTs) have compared direct oral anticoagulants (DOACs) with LMWHs. The aim of this systematic review and meta-analysis was to evaluate efficacy and safety of DOACs versus LMWHs and update the evidence for treatment of VTE in cancer.

Methods: Biomedical databases were screened for RCTs evaluating DOACs for cancer-associated VTE. Primary efficacy and safety outcomes of this meta-analysis were recurrent VTE and major bleeding at 6 months. Secondary outcomes comprised clinically relevant nonmajor bleeding (CRNMB), major gastrointestinal (GI) and genitourinary bleeding, mortality, fatal bleeding/pulmonary embolism, and treatment discontinuation rate. We performed prespecified subgroup analyses. Pooled relative risk (RR) and 95% confidence intervals (CIs) were obtained by the Mantel-Haenszel method within a random-effect model.

Results: We screened 759 articles and included 4 RCTs (n = 2894). DOACs significantly reduced recurrent VTEs compared to LMWHs (5.2% vs 8.2%; RR, 0.62 [95% CI, 0.43-0.91]), but were associated with a nonsignificant increase in major bleedings (4.3% vs 3.3%; RR, 1.31 [95% CI, 0.83-2.08]) and a significant increase in CRNMB (10.4% vs 6.4%; RR, 1.65 [95% CI, 1.19-2.28]). Mortality risks were comparable between groups (RR, 0.99 [95% CI, 0.83-1.18]). Preterm treatment discontinuation was less common with DOACs (RR, 0.88 [95% CI, 0.81-0.96]). Major bleeding was more frequent in patients with GI cancer treated with DOACs (RR, 2.30 [95% CI, 1.08-4.88]).

Conclusion: In patients with cancer-associated VTE, DOACs are more effective in preventing recurrent VTE compared to LMWH. However, risk of bleeding is increased with DOACs, especially in patients with GI cancer.