Primary Venous Thromboembolism Prophylaxis in Ambulatory Cancer Patients

OBJECTIVE: To summarize and review current medical literature regarding the efficacy and safety of antithrombotic therapy for primary venous thromboembolism (VTE) prophylaxis in various ambulatory cancer populations. DATA SOURCES: A literature search was conducted in PubMed (1966-September 2012) and International Pharmaceutical Abstracts (1970-September 2012) using the terms venous thromboembolism, primary prophylaxis, anticoagulation, antithrombotic agents, cancer, and ambulatory. The bibliographies of pertinent studies and topic articles were reviewed for additional references. STUDY SELECTION AND DATA EXTRACTION: All English-language articles were evaluated for inclusion. All randomized trials were included in the review. DATA SYNTHESIS: Malignancy has been identified as a major independent risk factor for the development of VTE in the surgical, medically ill, and ambulatory populations. Primary VTE prophylaxis has been identified as an area of great impact in cancer patients because of the difficulties associated with the treatment of VTE and the greater risk for its recurrence in this population. Although primary VTE prophylaxis is recommended in all surgical and hospitalized cancer patients without contraindications to anticoagulants, its role in ambulatory cancer patients is less certain because of varying patient, cancer, and treatment-related factors. Fourteen randomized studies have investigated the use of antithrombotic agents for primary VTE prophylaxis in ambulatory cancer patients. Strong evidence for primary prophylaxis exists for several populations with advanced or metastatic cancer considered to be at high risk, including those with pancreatic cancer, lung cancer, or multiple myeloma. Evidence is inconsistent or lacking for lower risk cancer populations, such as those with breast cancer, or for those with malignant glioma, which carries a high risk for VTE and bleeding relative to the general ambulatory cancer population. CONCLUSIONS: Use of antithrombotic agents has reduced the rate of primary VTE, with minimal increases in bleeding risk in specific ambulatory cancer populations. Further investigation is needed to guide and narrow recommendations for primary VTE prophylaxis in ambulatory cancer patients.