Primary VTE Prevention for Patients with Cancer

Based on results from randomized trials, current guidelines recommend primary prophylaxis against venous thromboembolism (VTE) for high-risk outpatients with cancer (J Clin Oncol 2023; 41:3063). However, few ambulatory patients with cancer receive VTE prophylaxis. Australian investigators identified 200 high-risk outpatients — defined as those with either elevated fibrinogen or D-dimer levels — who were being treated for gastrointestinal (GI) or lung cancer and randomized them to receive either low-molecular-weight heparin (LMWH) VTE prophylaxis or no prophylaxis. In addition, 128 low-risk patients (without elevation of fibrinogen or D-dimer) were followed in a low-risk observational arm.

In the randomized comparison between LMWH and no LMWH among high-risk patients, the LMWH group had significantly fewer thromboembolic events (8% vs. 23%; number needed to treat, 7) and significantly lower 6-month mortality (13% vs. 26%; NNT, 6). In the low-risk observational cohort, thromboembolism occurred in 8% of patients, and 6-month mortality was 7%. Bleeding was uncommon (<2%) and not different among groups.