Anticoagulation for the prevention of arterial thromboembolism in cancer patients by primary tumour site: a systematic review and meta-analysis of randomized trials.

Aims: The incidence of arterial thromboembolism (ATE) among ambulatory cancer patients varies by primary tumour site. However, it is unclear whether this alters the benefit-to-harm profile of prophylactic anticoagulation for ATE prevention. Therefore, we systematically evaluated the efficacy and safety of anticoagulants for ATE prevention among ambulatory cancer patients according to the primary tumour site.

Methods And Results: We conducted a systematic review using Medline, Embase, SCOPUS, and CENTRAL, and included randomized trials comparing prophylactic anticoagulation to no anticoagulation among ambulatory cancer patients who initiated tumour-directed systemic therapy. The incidence of symptomatic ATE (acute ischaemic stroke, acute myocardial infarction, or peripheral artery occlusion) and major bleeding, as well as risk differences (RDs) attributable to anticoagulation, were meta-analysed by primary tumour site using random-effects modelling. We included 10 randomized controlled trials with 9875 patients with follow-up ranging from 3.3 to 68 (median 6.6) months. While prophylactic anticoagulation did not reduce ATE risks overall (RD -0.49%; 95% CI -0.49% to 0.01%; I2 = 0%), it conferred a protective effect among pancreatic cancer patients (RD -3.2%; 95%CI -5.7% to -0.8%; I2 = 0%) without a detectable increase in major bleeding (RD -1.4%; 95% CI -4.6% to 1.8%; I2 = 0%). Prophylactic anticoagulation was not associated with ATE risk reduction in other tumour sites.

Conclusion: Based on available evidence, prophylactic anticoagulation did not reduce ATE risk among ambulatory cancer patients overall. However, we observed a lower incidence of ATE among pancreatic cancer patients randomized to receive anticoagulation. Prophylactic anticoagulant use to reduce ATEs in pancreatic cancer should be evaluated in future research.