Direct oral anticoagulants (DOAC) are now recommended for the treatment of cancer-associated thrombosis (CAT) based on the results of dedicated trials demonstrating that DOAC are non-inferior to low molecular weight heparins in preventing recurrent venous thromboembolism (VTE) in this population. The definition of "cancer patient" differs substantially among studies. Whether patients with active cancer and those with a history of cancer (HOC) carry the same risks of recurrent VTE and bleeding remains unclear. Few studies reported data on the efficacy and safety of anticoagulants according to active cancer or HOC categories. While in subgroup analyses of EINSTEIN and HOKUSAI the rates of recurrent VTE and bleeding did not differ between these categories, results from a subgroup analysis of AMPLIFY, from HOKUSAI-Cancer, and from the COMMAND cohort suggest that HOC patients might have a lower bleeding risk than active cancer patients. Whether the inclusion of HOC patients in CAT studies might introduce some bias by decreasing the rates of both recurrent VTE and bleeding remains an unanswered issue since no dedicated prospective study addressed this question. A strict definition of active cancer should be used in further trials.
Keywords: active cancer; anticoagulant; cancer-associated-thrombosis; history of cancer.