• Cancer and Thrombosis
• Risk factors
• FAQ

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Cancer and Thrombosis

Cancer increases your risk of developing a venous thromboembolism (VTE) which includes deep vein thrombosis (DVT) and pulmonary embolism (PE).

Cancer patients are between 5 and 7 times more likely to develop VTE⁽¹⁾

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Why does cancer increase your risk of thrombosis?

There are multiple ways that cancer can increase your risk of developing blood clots. Tumours often compress blood vessels, which allows blood to pool and be more likely to form a clot. Cancers may also release chemicals which cause the body to produce more clots.

Below is a list of factors that increase your risk of VTE with cancer:

1. Stage of the cancer
   • The more advanced or metastatic the cancer, the more risk of developing VTE
2. Chemotherapy
   • Chemotherapy carries a 7 times increased risk in developing a VTE.
   • Cancer treatment can damage your blood vessels and cause your cells to release molecules which increase the likelihood of clotting
3. Hospitalisation
   • Immobility and major surgery are general risk factors for VTE which are common for cancer patients to experience
4. Central venous catheters (CVC)
   
   • A CVC is inserted into a vein (usually the superior vena cava, under your right collarbone) to provide fluids, drugs, or blood transfusions directly into your blood stream.
5. Site of the cancer
   • Certain sites of cancer carry a higher risk of thrombosis. For example, stomach and pancreas have the highest risk, followed by lung, lymphoma, gynecological, testicular and bladder, followed by others).
6. Age
   • Patients over 70 have a 2-fold increase in risk over middle-aged patients.
7. Personal or family history of VTE
   • If you or your parents/grandparents have previously experienced a DVT or PE.
8. Other conditions
   • Including heart disease and current infections

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To learn more about thrombosis and its risk factors click here.

To download a leaflet version of this page click here.

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Cancer and thrombosis FAQs:

Why does cancer increase the risk of thrombosis?

This is not fully understood. However, it is thought that tumours can compress blood vessels and release chemicals which trigger blood clotting. Additionally, cancer is thought to cause damage and inflammation which can also trigger clotting.

Are certain cancers more likely to result in thrombosis?

Being hospitalised for any cancer increases your risk of thrombosis, but certain cancers have a greater risk. Cancers with a greater risk of thrombosis include brain, pancreatic, ovarian, stomach, lung, and kidney cancers have the highest risk of thrombosis. Blood and liver cancer also carries a higher risk of developing thrombosis. Stomach and pancreas cancers carry the highest risk, followed by lung, lymphoma, gynecological, testicular and bladder followed by others.

Does chemotherapy increase the risk of thrombosis?

Chemotherapy can increase the chances of developing thrombosis. This is not fully understood, but it is thought that the chemotherapeutic drugs damage blood vessels and cause changes in the level of anti-clotting factors in the blood. Both factors increase your chance of developing thrombosis.

How is my thrombosis treated?

If a cancer patient develops a deep vein thrombosis (DVT) or pulmonary embolism (PE) they are usually put on anticoagulant or blood-thinning medication to lower their risk of a second thrombosis for the entire duration of cancer treatment. This may be stopped after achieving a durable remission for the cancer. Changes to the diet may be recommended, as well as certain exercise recommendations. Compression stockings may also be recommended. You should always discuss options with your healthcare professional as every individual is different and may require different treatment.

How can thrombosis be prevented in cancer patients?

Because the risk of thrombosis is higher in both cancer patients and in people who have become hospitalised in general, it is important to know what can be done to lower this risk. Your doctor may recommend the use of anticoagulant medication or compression stockings which both help to reduce the chance of blood clots. Moving around as much as possible is very beneficial to reducing your risk of thrombosis. Finally, be aware of the signs and symptoms of a DVT or PE and warn your doctor at once if you are experiencing any of them.

Learn more about thrombosis.  

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Sources:

1. All-Party parliamentary Thrombosis Group. Venous Thromboembolism (VTE) in Cancer Patients. October 2016. 
2. Razak, N., Jones, G., Bhandari, M., Berndt, M., and Metharom, P. Cancer-Associated Thrombosis: An Overview of Mechanisms, Risk Factors, and Treatment. Cancers 2018; 10(1): 380. 
3. Khorana, A.A., Kuderer, N.M., Culakova, E., Lyman, G.H. and Francis, C.W., 2008. Development and validation of a predictive model for chemotherapy-associated thrombosis. Blood, 111(10), pp.4902-4907.