Blood clots

People with breast cancer have a higher risk of blood clots. Some treatments for breast cancer also increase the risk of blood clots.

If the breast cancer has spread to other parts of the body
(secondary breast cancer), this can also increase the risk.

Blood clots can be life-threatening but are treatable, so it’s important to report any symptoms as soon as possible.

If you are having treatment and develop a blood clot, your treatment may be paused until the blood clot has been treated.

Blood clots can happen naturally, for example your blood will clot after an injury to reduce bleeding.

But there are times when blood clots can be harmful and need treatment.

Deep vein thrombosis (DVT) is when a blood clot forms in a deep vein, usually the leg. Sometimes a blood clot can form in the arm, but this is much less common.

If a blood clot breaks away from the DVT and travels to another part of the body, it can block a blood vessel. If it travels to the lungs, it’s known as a pulmonary embolism (PE).

Blood clots can be life-threatening and should be treated quickly.

Breast cancer treatments that can increase the risk of blood clots

Some treatments for breast cancer can increase the risk of developing a blood clot. These include:

• Surgery – the risk of developing blood clots is highest 2 to 10 days after surgery and remains higher than normal for up to 90 days
• Chemotherapy 
• Targeted therapies
• Hormone therapies such as tamoxifen and fulvestrant

If you’re due to have surgery or any of the treatments listed above, let your treatment team know if you have a previous history of blood clots.

Having a central line 

A central line is a tube that’s inserted into a large vein. It can be used to give chemotherapy or targeted therapies. Blood samples can also be taken from a central line.

If you have a central line, such as a Hickman line, PICC line or portacath, it’s possible for a blood clot to form in a vein at the end of the line.

If this happens, your treatment team may need to give you some medication to treat the clot. 

The line may need to be removed if the clot doesn’t dissolve.

Your treatment team will let you know if this will affect your treatment.

Being less active due to treatment 

Breast cancer and its treatment can make you feel very tired or cause joint and muscle pain. This means you may not be as physically active.

If you have surgery, you may not be as mobile as you would normally be in the days and weeks after your operation.

Not moving around increases the risk of a blood clot. This is because the normal action of the leg muscles helps squeeze the veins to return the blood back towards the heart.

Being inactive on long travel journeys, such as long-haul flights, can also increase the risk of developing a blood clot.

You can find out more about DVT and how to reduce your risk on the NHS website.

Other things that can increase the risk of blood clots include:

• Being over 60 years old
• Heart disease
• Diabetes
• Smoking
• A previous history of blood clots
• Fractures
• Some forms of oral contraception and hormone replacement therapy (HRT)
• Pregnancy
• Being overweight
• Dehydration
• Prolonged travel (over 4 hours)

Ways you can reduce your risk

There are ways you can reduce your risk of developing a blood clot while having breast cancer treatment:

1. Regular physical activity – take short walks or do some simple leg and foot exercises if you cannot move around much, such as bending and straightening your toes
2. Drink plenty of water to keep hydrated
3. Eat a balanced diet and try to maintain a healthy weight
4. Take particular care on long car or train journeys or long-haul flights – move around regularly, keep hydrated and consider wearing compression stockings

If you're having an operation 

If you need to stay in hospital, the team looking after you should assess your risk of developing a blood clot.

If you’re having an operation, you may need to stop taking some of your usual medication before surgery. Your treatment team will let you know which medications you should stop taking and how long before your operation you need to stop them. They will also tell you when you will need to restart your medication.

You may be given anti-embolism or compression stockings to wear. These help the blood return towards the heart. Your treatment team will tell you how long you need to wear them after your operation.  

In some situations, such as immediately after surgery, a device called an intermittent compression system is used for a short time. This is a plastic sleeve worn around your foot, calf and thigh. It’s connected to a small machine which gently inflates the sleeve and squeezes your leg, increasing the blood flow through the veins.

Blood clots are diagnosed using an ultrasound scan or an x-ray.

Blood clots are usually treated with drugs that thin the blood (anticoagulants). These drugs are given as an injection at first but then may be changed to a tablet. These allow the body to absorb the blood clot over time and reduce the risk of future blood clots.

There are different drugs that thin the blood. Your treatment team or GP will let you know which one is right for you.

Treatment for blood clots is usually recommended for 3 to 6 months, but it may be longer based on your individual situation.

You can find out more about treating blood clots on the NHS website.

If you think you may have a blood clot, contact your treatment team or NHS 111 immediately or go to your local A&E department straight away.

If you are concerned about blood clots or just want to talk things through, our nurses are ready to listen on our free helpline, below.