Prevention and Treatment of Venous Thromboembolism in Patients with Cancer

Abstract

Many patients who experience a venous thromboembolic event have cancer, and thrombosis is much more prevalent in patients with cancer than in those without it. Thrombosis is the second most common cause of death in cancer patients and cancer is associated with a high rate of recurrence of venous thromboembolism (VTE), bleeding, requirement for long-term anticoagulation and poorer quality of life. A literature review was conducted to identify guidelines and evidence pertaining to anticoagulation prophylaxis and treatment for patients with cancer, with the goal of identifying opportunities for pharmacists to advocate for and become more involved in the care of this population. Many clinical trials and several guidelines providing guidance to clinicians in the treatment and prevention of VTE in patients with cancer were identified. Current clinical evidence and guidelines suggest that cancer patients receiving care in hospital with no contraindications should receive VTE prophylaxis with unfractionated heparin (UFH), a low-molecular-weight heparin (LMWH) or fondaparinux. Patients who require surgery for their cancer should receive prophylaxis with UFH, LMWH or fondaparinux. Cancer patients who have experienced a VTE event should receive prolonged anticoagulant therapy with LMWH (at least 3 months to 6 months). No routine prophylaxis is required for the majority of ambulatory patients with cancer who have not experienced a VTE event. Most publicly funded drug plans in Canada have developed criteria for funding of LMWH therapy for patients with cancer. Evidence suggests that LMWH for 3 to 6 months is the preferred strategy for most cancer patients who have experienced a thromboembolic event and for hospital inpatients, but this is often not implemented in practice. Concerns about adherence with injectable therapy should not prevent use of these agents. Pharmacists should assess cancer patients for their risk of VTE and should advocate for optimal VTE pharmacotherapy as appropriate. If LMWH is the preferred agent, on the basis of the evidence, the pharmacist should educate the patients appropriately and work with the prescriber to ensure best care.