Is prophylactic anticoagulation effective in preventing venous thromboembolic events in outpatients with cancer receiving active chemotherapy?

Abstract

In outpatients with active cancer on chemotherapy, treatment with low-molecular-weight heparin (LMWH) reduces the risk of symptomatic venous thromboembolism (VTE) compared with no thromboprophylaxis (number needed to treat 37), whereas warfarin and the direct oral anticoagulants apixaban and rivaroxaban do not significantly reduce VTE risk compared with placebo (SOR: A, systematic review of randomized controlled trials [RCTs]). However, LMWH (but not warfarin, apixaban, or rivaroxaban) increases the risk of major bleeding (number needed to harm 144) when compared with placebo or no thromboprophylaxis (SOR: A, systematic review of RCTs). Oncology guidelines recommend offering rivaroxaban, apixaban, or LMWH to cancer patients on chemotherapy who are at intermediate to high risk of VTE and have a low risk of bleeding, after shared decision making. Guidelines recommend against routine use of anticoagulation in all ambulatory patients with cancer on systemic therapy (SOR: C, expert opinion).