Mechanisms of hypercoagulation in malignancy and during chemotherapy.

Patients with cancer are at increased risk for thromboembolic disease. Commonly they present with abnormalities of one or more circulating markers of haemostatic system activation, underlying a 'hypercoagulable state'. Despite numerous investigations which have identified alterations in all of the haemostatic components (i.e. coagulation, fibrinolysis, endothelium, platelets and monocytes), no firm conclusions have been reached regarding the clinical utility of any of these coagulation markers for predicting thrombosis in cancer patients. The predictive value of one or more of these tests could help to identify safe and effective methods for prophylaxis against thrombotic complications in these patients. Plasma clotting abnormalities are usually exacerbated by chemotherapy. The mechanisms by which the haemostatic system is activated in malignancy (and chemotherapy) are reviewed.