Clotting Problems

Approved by the Cancer.Net Editorial Board, 08/2016

A blood clot is a serious condition that needs immediate treatment. People with cancer and those receiving cancer treatment are at an increased risk for blood clots.

Normal blood clotting, called coagulation, is a complex process. Specialized blood cells called platelets and different proteins in the blood called clotting or coagulation factors clump together to heal broken blood vessels and control bleeding. There is a delicate balance between coagulation factors that promote bleeding and those that promote clotting. Blood clotting disorders occur when some clotting factors are missing or damaged and form clots inside the body. These clots can block the normal blood flow and cause serious problems.

Blood clots can occur in and travel to different parts of the body, including:

  • Veins, called a deep venous thrombosis (DVT)

  • The lungs, called a pulmonary embolus (PE)

  • An artery (less common but also very serious)

Signs and Symptoms of clotting problems

Relieving side effects is an important part of cancer care and treatment. This is called symptom management, palliative care, or supportive care. Talk with your health care team about any symptoms you experience and any change in symptoms.

People with clotting problems may experience:

  • Arm or leg swelling on one side of the body

  • Pain in the arm or leg where a blood clot is located

  • Trouble breathing or chest pain when breathing

  • Rapid heart beat

  • Low oxygen levels

Tell your doctor about any of these symptoms immediately. It is important to know that even patients with low levels of platelets can develop a blood clot. Sometimes patients do not know they have a blood clot until it is diagnosed during a test.

Causes of clotting problems

People with cancer have a higher risk of blood clots and clotting disorders. These may be caused by the cancer or the treatment, such as chemotherapy, surgery, medications called steroids, and the long-term use of a catheter. Long periods of inactivity, such as a long plane or car ride can also increase the risk of a blood clot.

Diagnosing clotting problems

Your doctor may use one or more techniques to diagnose a blood clot:

  • A Doppler ultrasound. This test uses sound waves to look at the flow of blood in veins in the arms or legs. It can detect decreased blood flow from a blood clot.

  • A computed tomography (CT) scan. A CT scan creates a three-dimensional picture of the inside of the body using x-rays taken from different angles. A special dye called a contrast is injected into a patient’s vein before the scan to provide better detail on the image. Doctors commonly use CT scans to diagnose a blood clot in the lungs, or PE.

  • A lung ventilation/perfusion (VQ). This test, which can also diagnose PE, is made up of two different parts: the ventilation scan that looks at the airflow in the lungs and the perfusion scan that looks at the blood flow in the lungs.

  • An angiogram. This test can detect a blood clot in an artery. During an angiogram, a dye is injected into the artery. And then the artery is examined with a special x-ray device called a fluoroscope.

Managing clotting problems

A blood clot needs immediate treatment. The most common treatment is to start blood thinners either by injection under the skin or into a vein. Once the blood is considered thin enough, there is no longer a risk of clotting. At this point, some patients can begin taking a blood thinner pill that is swallowed.

Patients who are receiving blood thinners need to be regularly monitored so that there is no increased bleeding. Some patients are unable to receive blood thinners because they have low platelet levels or a high risk of bleeding. For these patients, a special type of filter can be placed in the body to prevent a blood clot from traveling to the lungs, which can be very dangerous.

More Information

Preventing and Treating Blood Clots

Side Effects