Cancer and Pulmonary Embolism Development

Approximately 1-2% of cancer-related deaths are caused by pulmonary emboli, a type of blood clot in the lungs.

These clots can cut off the lungs’ blood supply, leading to death. About 5-10% of pulmonary emboli are considered life threatening.

What causes a pulmonary embolism?

A pulmonary embolism actually starts in the leg or pelvis, where the clot is called a deep vein thrombosis. In some cases, a piece of that clot breaks off from a vein in the leg or pelvis. It then travels through the circulatory system and ends up in the pulmonary artery, blocking the supply of blood to the lungs. At that point, it is called a pulmonary embolism.

There are many triggers that can lead to the formation of a deep vein thrombosis/pulmonary embolism in cancer patients. Some types of cancer are more likely to cause these clots, including

• acute leukemia
• glioblastoma
  
• kidney cancer
• lung cancer
• pancreatic cancer.

Several cancer treatments can also lead to blood clots, such as chemotherapy and hormone therapy. Patients who undergo surgery, are immobile or who have central venous catheters are also at an increased risk of developing these clots.

What are the symptoms of a pulmonary embolism?

The main symptoms of a deep vein thrombosis are pain and swelling in the calf, behind the knee and up into the thigh, all in one leg. The main symptoms of a pulmonary embolism are sudden shortness-of-breath and chest pain.

Deep vein thromboses and pulmonary emboli are diagnosed by imaging exams: ultrasound/Doppler study for a deep vein thrombosis and chest CT angiography for a pulmonary embolism.

How is a pulmonary embolism treated?

For both deep vein thromboses and pulmonary emboli, patients are given blood thinners to prevent new clots from forming and existing clots from spreading. This gives the body a chance to digest the dangerous clot and heal itself.

How the body heals itself depends on where the clot is located. If treated, a pulmonary embolism should dissolve with time. A deep vein thrombosis, however, will never clear up entirely. Instead, the body will cover the clot with layers of cells that smooth it over, stabilize it and prevent it from growing and breaking.