Cancer and thrombosis: Managing the risks and approaches to thromboprophylaxis

Patients with cancer are at increased risk of venous
thromboembolism (VTE) compared with patients without cancer. This
results from both the prothrombotic effects of the cancer itself
and iatrogenic factors, such as chemotherapy, radiotherapy,
indwelling central venous devices and surgery, that further
increase the risk of VTE. Although cancer-associated thrombosis
remains an important cause of morbidity and mortality, it is often
underdiagnosed and undertreated. However, evidence is accumulating
to support the use of low-molecular-weight heparins (LMWHs) in the
secondary prevention of VTE in patients with cancer. Not only have
LMWHs been shown to be at least as effective as coumarin
derivatives in this setting, but they have a lower incidence of
complications, including bleeding, and are not associated with the
practical problems of warfarin therapy. Furthermore, a growing
number of studies indicate that LMWHs may improve survival among
patients with cancer due to a possible antitumor effect. Current
evidence suggests that LMWHs should increasingly be considered for
the long-term management of VTE in patients with cancer.