Anticoagulation in patients with cancer: an overview of reviews

Introduction. Relative benefits and harms of anticoagulants are required for judgments regarding appropriate anticoagulation in patients with cancer. Objectives. To review the benefits and harms of anticoagulants for prophylactic, therapeutic, and survival improvement indications in patients with cancer. Patients and methods. Overview of 6 systematic reviews of anticoagulation in cancer following the Cochrane Collaboration and Grading of Recommendations Assessment, Development and Evaluation methodology. Results. Central venous catheters thromboprophylaxis with heparin or warfarin does not significantly reduce the incidence of symptomatic deep vein thrombosis (DVT) (relative risk [RR] 0.43, 95% CI 0.18–1.06 and RR 0.62, 95% CI 0.30–1.27 respectively). For perioperative thromboprophylaxis, low‑molecular‑weight heparin (LMWH) and unfractionated heparin (UFH) have similar effects on mortality (RR 0.89, 95% CI 0.61–1.28) and morbidity outcomes. For the initial treatment of venous thromboembolism (VTE), LMWH compared with UFH reduces mortality at 3 months (RR 0.71, 95% CI 0.52–0.98). For the long-term treatment of VTE, LMWH compared with vitamin K antagonists reduces VTE recurrence (hazard ratio [HR] 0.47, 95% CI 0.32–0.71) but not mortality (HR 0.96, 95% CI 0.81–1.14). As interventions to improve survival, warfarin suggests a survival benefit at 6 months in the subgroup of small cell lung cancer (SCLC) (RR 0.69, 95% CI 0.50–0.96) while heparin suggests a survival benefit in patients with cancer in general (HR 0.77, 95% CI 0.65–0.91) and in those with limited SCLC in particular (HR 0.56, 95% CI 0.38–0.83). Conclusions. In patients with cancer, current evidence does not support routine use of thromboprophylaxis for central venous catheters or a specific anticoagulant for perioperative thromboprophylaxis. Anticoagulants may improve survival, but more data will be useful in deciding which subgroups benefit most.