[Thromboembolic events in malignant diseases]

There is a bidirectional connection between tumors and thrombosis. On one hand, thromboembolic events are more frequent in cases of malignancies, on the other hand, proliferation of tumor cells, progression of the malignant process and metastasis formation are facilitated by the activation of the hemostatic system. Thromboembolic events are associated with a worse prognosis in case of patients with malignant diseases. Thromboembolism is the second most frequent cause of death in patients with malignant tumors. Mortality is twice as high in patients with thromboembolism compared to those without it. The incidence of thromboembolism shows an increasing tendency. There has been a 28% increase among hospitalized cancer patients between 1995 and 2003. One reason is that the new anti-tumor agents have more pronounced prothrombotic activity than those of traditional chemotherapeutic drugs. Assessment of the thrombotic risk of cancer patients becomes more important. Several guidelines have been published concerning the prevention and treatment of thromboembolism in patients with malignancy. The risk of thrombosis is influenced not only by the type of malignancy but there are also large individual differences. Furthermore, the risk of thrombosis changes during the disease process in the same patient. Perioperative thromboprophylaxis is a very important issue considering oncologic surgery. Thromboprophylaxis of oncologic patients has a high significance in respect of morbidity and mortality. However, thromboprophylaxis may also cause serious complications thus the correct risk assessment of cancer patients is very important.