Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is a major complication of cancer and one of the leading causes of death among cancer patients.1, 2 Overall, approximately 20% of all VTE cases occur in patients with cancer.3 In addition, VTE affects up to 20% of patients with cancer before death and has been reported in up to half of cancer patients at the time of postmortem examination, highlighting the fact that the true extent of this complication may be underestimated.4, 5 Cancer-associated VTE has important clinical and economic consequences, including increased morbidity resulting from hospitalization and anticoagulation use, bleeding complications, increased risk of recurrent VTE, and cancer treatment delays.6 In 1 analysis, Prandoni et al reported that patients with cancer and VTE were approximately 4 times more likely to develop recurrent thromboembolic complications and twice as likely to develop major bleeding while receiving anticoagulant treatment than those without malignancy.7 The occurrence of VTE in patients with cancer may interfere with planned chemotherapy regimens, worsen patient quality of life,8 and lead to the increased consumption of healthcare resources compared with patients without cancer who experience VTE. In a retrospective study of medical records from 529 cancer patients, the mean hospitalization cost for DVT was $20,065 per episode (2002 US$)9 compared with a cost of $7712 to $10,804 per episode in a general medical population with VTE.10
VTE is also associated with increased mortality in cancer patients. A retrospective study by Khorana et al found that in-hospital mortality was 2-fold to 5-fold more common in neutropenic cancer patients hospitalized with thromboembolism compared with those without thromboembolism.11 Similarly, Chew et al determined that the diagnosis of VTE was a significant predictor of increased mortality during the first year among all cancer types examined, with hazard ratios (HRs) ranging from 1.6 to 4.2 (P < .01).12 The strongest predictor of death in this analysis was metastatic disease at the time of cancer diagnosis, with an HR ranging from 1.8 to 49.0 (P < .001). In addition, stratified analyses demonstrated that VTE was associated with an increased risk of death for patients with all stages and cancer types, with a median overall relative risk (RR) of 3.7 (Table 1).12 A prospective study of patients initiating new chemotherapy (median follow-up, 75 days) found that VTE accounted for 9.2% of deaths.1 In addition, a VTE diagnosis has been associated with an approximately 2-fold increased risk of death within 2 years in patients with breast cancer.13
|HR by Stage|
Taken together, these data highlight the need for close monitoring, prompt treatment, and appropriate preventive strategies for VTE in patients with cancer. This review will describe the substantial impact of VTE on patients with cancer, the effects of VTE on clinical outcomes, the importance of thromboprophylaxis in this population, relevant ongoing clinical trial data, and new pharmacologic treatment options for the prevention of VTE.