Low- molecular-weight heparin agents are commonly used empirically when a hypercoagulable state is suspected, but the benefit is unclear,654 particularly in this patient population with a high tendency for hemorrhage.651 A specific situation in these patients that has been more adequately studied is the best anticoagulation regimen for the prevention of cardioembolism from AF,651 which is extrapolated from subgroup analysis of the large ran- domized clinical trials of anticoagulation. (We also refer the reader to Section 5.13.3, Neoplastic Vasculitis.) Recommendation-Specific Supportive Text 1. A subgroup analysis in the ROCKET AF trial comparing rivaroxaban and warfarin in patients with AF and history of cancer showed similar rates of stroke and systemic embolism 0.52 (95% CI, 0.22 1.21) and nonmajor bleeding Similarly, were comparable to those of warfarin in patients with AF and history of cancer in the ARISTOTLE This was supported by claims data analy- sis looking at bleeding events of rivaroxaban CLINICAL STATEMENTS AND GUIDELINES Kleindorfer CI, 0.17 0.79]) compared with warfarin.649 A lit- erature search of 31 660 patients in 5 trials in patients with AF and cancer DOACs showed a trend for more efficacy and better safety com- pared with warfarin.650 Knowledge Gaps and Future Research Patients who had a stroke attributable to hyper- coagulability from cancer may be at a particularly high risk of bleeding with anticoagulation. In these patients, the benefit of anticoagulants for second- ary stroke prevention is not well established, and further research is needed. The particular need of anticoagulation to prevent stroke in different type of cancers is not known and should be a matter of further research. In patients who had a stroke attributable to hyper- coagulability from cancer who are anticoagulated, there is a paucity of data on the best treatment regi- men for these patients. 