An important consideration with the new oral anticoagulant agents is that they are not currently recommended for us in patients with active cancer.  The American Society of Clinical Oncology (ASCO) has listed several concerns.  As shown in Figure 20,[15] these include: 

       •       there were few patients with an active malignancy enrolled in these randomized trials; 

       •  there may be unpredictable absorption in this particular population;

       • it is reasonable to think that a patient with mucositis may have a higher risk of gastrointestinal (GI) bleeding or other GI                         complications; and 

       • in patients on chemotherapy there is decreased food and drug intake and there may be altered metabolism in patients                       with liver or some renal impairment.

In addition, drug interactions with hormonal and chemotherapy agents have not been studied, and in these patients at higher risk, not only for thrombosis but also bleeding complications, the inability to measure the anticoagulant activity using readily available assays at community hospitals and highly specialized tertiary hospitals may be an issue.  Finally, because of all this uncertainty the lack of an antidote at this time may be a particularly important issue for this patient population.  Hylek E. Am J Med 2013; published on-line at http://education.amjmed.com/00000.