[Venous thrombosis and cancer].

The incidence of newly diagnosed cancer is increased, among patients with idiopathic venous thromboembolic event (VTE), six to twelve months after the diagnosis. Among these cancers, the most common sites are colorectal, prostate, pancreas, lung and ovary cancers. However, no study has provided convincing evidence that a patient with idiopathic VTE should undergo an extensive search for underlying cancer. An hypercoagulable state is observed in cancer patients, as shown by abnormal "routine" blood tests found in up to 90% of these patients, as well as increased levels of specific markers of coagulation activation. Clinically, these abnormalities are expressed as thrombosis, hemorrhage or low grade or fulminant disseminated intravascular coagulation. The pathophysiology of this thrombophilic state is complex and due to interactions of tumor cells and their products with host cells. Cancer patients are thus at high risk of thrombosis and so far no biological test can predict the VTE. In special conditions, as surgery or during chemotherapy, prophylaxis with various forms of heparins or oral anticoagulant are recommended.