Should you give primary prophylaxis for venous thromboembolism to patients with cancer?

In ambulatory patients with cancer, primary thromboprophylaxis with direct factor Xa inhibitors may reduce the incidence of symptomatic venous thromboembolism (VTE; low‐certainty evidence) and probably increases the risk of major bleeding (moderate‐certainty evidence) when compared with placebo.

Low‐molecular‐weight heparin (LMWH) reduces symptomatic VTE, with 37 participants requiring prophylaxis to prevent 1 event (high‐certainty evidence). This benefit comes at the cost of a higher incidence of major bleeding – for each 144 participants treated, 1 event is expected to occur when compared against placebo or no thromboprophylaxis (moderate‐certainty evidence).

Evidence for the use of thromboprophylaxis with anticoagulants other than direct factor Xa inhibitors and LMWH is limited.