NOACs can be given with fixed dose regimens without routine coagulation monitoring because of the specific anticoagulant activities (Figure 1), relatively fast onset/offset of actions, and little food or drug interactions. Their efficacy and safety for atrial fibrillation (AF) management in the general population have been proven to be non-inferior to warfarin in various trials (Dogliotti et al., 2013; Larsen et al., 2016; Ruff et al., 2014), and adoption of these agents into clinical practice is growing. A cohort study of over 60,000 AF patients showed that NOAC therapy is replacing warfarin for the VTE management (Patel et al., 2015) and is expanding the indications into mechanical heart valves, heart failure, and coronary artery disease (Yeh et al., 2015). However, these new agents are not popular among oncologists, at least not yet, because of the relatively limited data in the VTE treatment for cancer patients and less familiarity with the agents (Sardar et al., 2015; Wharin and Tagalakis, …show more content…
A recent subset-analyses of cancer patients in NOAC trials have shown non-inferiority to standard therapy consisting of enoxaparin followed by dose-adjusted warfarin (Agnelli et al., 2015; Prins et al., 2014; Raskob et al., 2016; Schulman et al., 2015). Several systemic reviews and meta-analyses of clinical trial data also revealed some evidence for similar efficacy and safety between NOACs and the standard therapy (Hulle et al., 2014; Sardar et al., 2015; Vedovati et al., 2015). However, the extent of the disease or the status of cancer treatment was not described in detail and may affect the outcome of anticoagulation therapy. In addition, these results should be interpreted with caution because of the enrollment of only a small proportion of cancer patients, different definition of active cancer as well as various inclusion criteria for cancer patients (patients with cancer history and patients with new onset of