Thrombosis and cancer

Although the association between malignant disease and thrombosis was first recognised by Trousseau in 1865, many aspects of this complex relationship are still obscure. Cancer patients have an increased risk of developing thrombosis. Similarly, patients presenting with idiopathic venous thromboembolism are considered to have a higher risk of developing cancer. However, no data exist that warrant thorough screening for cancer in these patients--apart from history taking, physical examination, routine investigations, and chest X-ray. Tumour cells activate the blood coagulation system either by directly stimulating thrombin formation or by inducing mononuclear cells to synthesise procoagulants. Both cancer cells and chemotherapeutic agents damage the endothelium by further enhancing the hypercoagulable state of malignancy. With few exceptions, the diagnosis and treatment of thrombosis in cancer patients are the same as in patients without cancer. Cancer patients are considered eligible for primary prevention of venous thromboembolism when they are receiving chemotherapy, if they have indwelling central venous catheters, when they are immobilised and, more importantly, when they undergo surgery. Secondary prevention in recurrent venous thrombosis may require the administration of oral anticoagulants or, in cases of resistance to warfarin, adjusted doses of heparin.