Cancer-Associated Thrombosis Study Group

Patients with cancer are at risk for developing blood clots in their arms or legs. This condition is called deep venous thrombosis, or DVT. Occasionally, portions of the blood clot can break off and migrate through the circulatory system to the lungs, a condition called pulmonary embolism, or PE. PE can be life-threatening. Arterial thrombosis also occurs more frequently in cancer patients than in non-cancer patients. This can manifest as a heart attack or a stroke, and can also be life-threatening.

Learn more about Professor Trousseau, who discovered this association of cancer with thrombosis, and the history of cancer-associated thrombosis.

What are the Risk Factors for Cancer-associated Thrombosis?

Some cancer patients are more at risk for developing DVT or PE than other cancer patients. Risk factors include:

  • Type of cancer (pancreas, stomach, brain, ovary, kidney, lung and lymphoma have the highest risk)
  • Metastatic disease
  • Receiving active chemotherapy or hormonal therapy
  • Hospitalization
  • Recent surgery
  • Receiving drugs like bevacizumab (Avastin) and thalidomide or lenalidomide
  • High platelet count before starting chemotherapy

What are the Consequences of Cancer-associated Thrombosis?

DVT and PE have many consequences for cancer patients, including:

  • Risk of recurrence of DVT or PE
  • Requirement for long-term anticoagulation with a blood thinner
  • A 12% annual risk of major bleeding complications while on the blood thinner
  • Possible delay in delivery of planned chemotherapy
  • Negative impact on patients' quality of life
  • DVT, PE and arterial thrombosis together account for nearly 10% of deaths in cancer patients

What are the Symptoms of Cancer-associated Thrombosis?

Patients with DVT usually present with leg swelling (more in one leg than the other), leg pain, or redness along a vein in the calf. Such symptoms can also occur in the arms, although less commonly.

Patients with PE generally present with chest pain that worsens on taking a deep breath, shortness of breath, cough with blood-streaked sputum and fatigue. Symptoms of PE can start suddenly and require urgent medical attention.

Sometimes, DVT and PE can be without any symptoms, and be discovered incidentally on a CT scan done to evaluate the underlying cancer.

How is Cancer-associated Thrombosis Treated?

A variety of drugs are available to treat cancer-associated DVT or PE. These include warfarin or Coumadin, unfractionated heparin and low-molecular-weight heparins including enoxaparin, dalteparin and tinzaparin in the United States.

How can Cancer-associated Thrombosis be Prevented?

The use of blood thinning drugs such as heparin or low molecular weight heparins in hospitalized patients or patients undergoing surgery has been shown to reduce the risk of thrombosis in high-risk patients, including cancer patients. Additionally, use of stockings or intermittent pneumatic devices can also reduce the risk.

Read a discussion of ways to prevent thrombosis in hospitalized patients.

View guidelines for healthcare professionals on cancer-associated thrombosis from NCCN.

Cancer-Associated Thrombosis Information