Blood clots, cancer and you

If you are diagnosed with cancer, there will be a lot going through your mind, and blood clots probably aren’t going to be the first thing you think about.

It is worth remembering that developing a blood clot while living with cancer is far from unusual – up to 1 in 5 people with cancer will develop a clot.1

When you have cancer and a blood clot, it’s called ‘Cancer-Associated Thrombosis’ – or CAT for short.

As with all blood clots, CAT is serious – it is one of the leading causes of death in cancer patients, after cancer itself.2 ,3

There are effective medicines which can treat, or prevent further blood clots from forming.

Despite this, CAT is not commonly discussed.4

In the video above and on the page below is some information about blood clots in cancer, what to watch out for, and how to avoid them.


CAT is not your fault, it is not caused by anything you have done, some people are simply more likely to develop a clot than others.

There are a number of risk factors – being treated for cancer, being inactive (in hospital) and/or having surgery can also raise the risk of cancer-associated thrombosis.5

Particular types of cancer will also increase your risk of developing a clot, specifically:6

Your healthcare team should talk to you about clots and regularly review your risk throughout your treatment. If you aren’t sure if this has happened, feel free to ask.

Avoiding CAT

Fortunately, there are ways in which you can reduce your risk of CAT

Treatment for CAT

If you do develop a blood clot while being treated for cancer, there are effective treatments that can help manage your CAT and prevent further clots from forming.

Importantly, the treatment for CAT is different to that for deep vein thrombosis (DVT) or pulmonary embolism (PE).

The recommended treatment for CAT is an injected type of anticoagulant called low-molecular weight heparin (LMWH), every day for 6 months.7

It is important that you keep taking the treatment every day for at least 6 months, or for as long as your doctor advises.

If you are unclear on how to use your treatment, refer to the information inside the pack you received, known as the Patient Information Leaflet, or speak to your healthcare team.

Signs of clots

It is important to be aware of potential signs of clots.

Signs you may have a blood clot in your leg (DVT) include:

Or for a clot in your lungs (or PE):

If you are worried about clots, immediately contact your healthcare team.

The text for this page was developed in partnership with, and funded by LEO Pharma.

2013c/00089a  Date of Preparation: Oct 2015

  1. Chew H, et al. Incidence of Venous Thrombembolism and its effect on survival among patients with common cancers. Arch Intern Med. 2006;166:458-464. 

  2. Khorana AA, et al. Thromboembolism is a leading cause of death in cancer patients receiving outpatient chemotherapy. Journal of Thrombosis and Haemostasis. 2007;5(3):632-634. 

  3. Khorana AA. Venous thromboembolism and prognosis in cancer. Thromb Res. 2010;125(6):490-3. 

  4. Noble S, et al. Patients’ Experiences of LIving with CANcer-associated thrombosis: the PELICAN study. Patient Prefer Adherence. 2015;9:337-45 

  5. Gomes M, Khorana AA. Semin Thromb. Hemost. 2014;40(3):319-24. 

  6. Khorana AA et al., Incidence and predictors of venos thromboembolism (VTE) among ambulatory high-risk cancer patients undergoing chemotherapy in the United States. Cancer. 2013;119:645-55. 

  7. NICE Clinical Guidance 144. Available from Accessed October 2015