Recurrent thromboembolism in cancer patients: incidence and risk factors

In contrast with the paucity of data on the risk of a first episode of thrombosis in cancer patients, the frequency of recurrent thromboembolism in patients with malignancy has been extensively investigated, both during anticoagulation and after its cessation. Cancer patients are more likely to develop recurrent thromboembolism and major bleeding during anticoagulation than patients without malignancies. These events are more pronounced during the first weeks of treatment and increase with cancer severity. Since they are not associated with anticoagulant intensities outside the therapeutic range, possibilities for improvement using the current paradigms of anticoagulation seem limited and new treatment strategies should be developed. In this regard, the use of low-molecular-weight heparins for initial treatment and long-term anticoagulation in cancer patients with venous thrombosis seems promising. Furthermore, patients with active cancers exhibit a particularly high risk of recurrent venous thromboembolism after the cessation of anticoagulation. In view of the persisting high risk for recurrent thrombotic events in cancer patients, and the acceptable risk of bleeding, prolonged warfarin treatment should be considered in such patients for as long as the cancer is active.