This is a clinical practice guidelines for cancer patients who may be at risk for venous thromboembolism (VTE). The guideline provides recommendations on prophylaxis and the treatment of VTE in the outpatient, inpatient, and perioperative settings. Interventions considered include mechanical and pharmacologic thromboprophylaxis and patient education. The role of inferior vena cava (IVC) filters is also discussed. Outcomes of interest include symptomatic and asymptomatic thrombotic events found on screening, major and minor bleeding, mortality (early and overall), sudden death, and adverse events.