[Cancer and venous thromboembolism].

INTRODUCTION

Cancer and venous thromboembolism are frequently associated.

STATE OF THE ART

Venous thromboembolism is associated with a worse prognosis in patients with cancer. Thrombosis in cancer patients is related to the expression of tissue factor and other procoagulants by tumour cells. Surgery, chemotherapy and antiangiogenic agents are also associated with an increased risk of thrombosis. Venous thromboembolism may be the first manifestation of cancer, the risk being especially increased during the first six months following an unexplained episode of idiopathic thrombosis. Current evidence does not suggest that a systematic screening for cancer after an unexplained thrombosis is associated with a clinical benefit. Risk factors for thrombosis specific to the cancer population have been identified. A recent controlled trial suggests that low-molecular weight heparin may reduce the incidence of venous thromboembolism in patients with cancer. These results need to be confirmed. Treatment of venous thromboembolism in cancer patients is primarily based on low-molecular weight heparin administered for three or six months.

PERSPECTIVES

Low-molecular weight heparin may increase the survival of patients with cancer through a direct effect on tumour biology. Several clinical trials are underway to confirm this hypothesis.

CONCLUSION

Thrombosis in cancer patients is a frequent and difficult to treat condition. The role of long-term prophylaxis remains to be defined. The treatment of venous thromboembolism in cancer patients is primarily based on low-molecular weight heparin. Large clinical trials are currently assessing the effect of low-molecular weight heparin on the long-term survival of patients with cancer.