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Blood Clots and Cancer: A Closer Look

Read Time: 4 minutes

Yazan Abou-Ismail, MD
Yazan Abou-Ismail, MD

Yazan Abou-Ismail, MD, assistant professor of at the , specializes in bleeding and clotting disorders. He explains how bleeding and clotting disorders can affect people with cancer.

What is a blood clot?

A blood clot is a clump of blood that has formed a gel-like mass blocking blood flow. If it occurs in an artery (the vessels that supply blood to the organs), it can lead to a heart attack, stroke, organ damage, or limb damage.

Another type of clot is called deep vein thrombosis. This occurs when a clot forms in a vein deep inside the body. It can cause a pulmonary embolism, when the clot travels to a lung and blocks an artery.

What are the signs of deep vein thrombosis and pulmonary embolism?

Signs of deep vein thrombosis include the following:

  • Swelling in one of the legs
  • Pain or tenderness not caused by injury
  • Warmth of the skin
  • Redness or discoloration of the skin

Signs of a pulmonary embolism include the following:

  • Shortness of breath or hard time breathing
  • Sudden chest pain that worsens with a deep breath or cough
  • Irregular or fast heartbeat
  • Coughing up blood

If you experience any of these side effects, call 911 or go straight to the emergency department.

How are blood clots treated?

There are different ways blood clots are treated:

  • Medication
    • Anticoagulants, commonly called blood thinners, help prevent clots from getting larger or traveling in the body. They help lower the risk of new blood clots from forming. The body then dissolves the clot on its own.
  • Compression socks
    • These socks or stockings help reduce the risk of developing blood clots in the leg veins. This treatment reduces the risk of post-thrombotic syndrome.
  • Surgery
    • An embolectomy is surgery to remove a blood clot from an artery or vein.
    • Filter placements help prevent blood clots from traveling to the lungs.

Most people do not require surgery. These procedures are only used in very special situations.

Is deep vein thrombosis serious?

It can be. Usually, blood clots that form in the leg veins remain stuck to the wall of the vein. With appropriate treatment (as noted above), blood clots usually resolve on their own. However, in some cases, these issues are possible:

  • Part of the blood clot breaks off and travels in the blood stream. It may reach the lungs, causing a pulmonary embolism, which can be life-threatening.
  • Ongoing issues happen in the calf, known as post-thrombotic syndrome or post-phlebitic syndrome. These may include calf pain, swelling, rashes, or ulcers.

Can cancer cause blood clots?

Yes, cancer is a known risk factor for blood clots. Certain types of cancer pose a greater risk for blood clots than others. These cancers increase the risk for blot clots:

Usually, the later the stage of the cancer, the greater the risk of blood clots.

Can cancer treatment cause blood clots?

Some types of chemotherapy or hormone therapy used in cancer treatment can increase the risk of blood clots. Other parts of cancer treatment, such as surgery, being in a hospital bed for long periods of time, and placement of catheters in the veins, can increase the risk of blood clots. Talk to your care team if you have any concerns about your risk for blood clots.

I recently had a blood clot. Does that mean I have cancer?

No. Having a blood clot does not mean you have cancer. There are many causes of blood clots. Clots are usually caused by triggers such as surgery or lack of body movement. In rare cases, blood clots can be due to cancer. Stay up to date on cancer screenings, whether or not you have ever had a blood clot.

How common are blood clots?

In the United States, an estimated 900,000 Americans a year get a blood clot. This results in around . Worldwide, blood clots are a leading cause of death and disability, with 1 in 4 people dying of conditions caused by blood clots.

What can I do to lower my risk of a blood clot?

  • Maintain a healthy weight
  • Eat a healthy diet
  • Stay active
  • Exercise regularly
  • Do not smoke
  • Avoid sitting for long periods
    • If you are going on a road trip, stop to take breaks and walk around.
    • If you are flying, move your legs regularly, stand up from time to time, and try to move around the plane. Flex your calf muscles while sitting.

If you have a strong family history of blood clots, talk with your doctor. They can help decide if testing or medications are safe and right for you. Some medications, such as oral contraceptives, may increase the risk of blood clots.

Cancer touches all of us.