Lung cancer can be accompanied by additional complications such as blood clots. Blood clots are blockages in blood vessels that prevent the proper flow of blood.

It is important to understand how lung cancer affects a person’s risk of blood clots, how to decrease their likelihood, and how to recognize their signs.

What Are Blood Clots?

Blood clotting, also called coagulation, is a normal process that occurs after a wound or cut. Blood clotting is how our bodies prevent excessive blood loss. At the site of injury, platelets (a type of blood cell) interact with special proteins to cause clotting. However, in an abnormal or unhealthy situation, blood clots can form in the blood vessels. These cause problems that stem from the lack of properly flowing blood.

A blood clot that forms in a vein is called a venous thromboembolism (VTE). Doctors commonly observe VTEs in people with lung cancer.

There are two types of VTE:

• Deep vein thrombosis (DVT), which forms in a deep vein in a leg or other limb
• Pulmonary embolisms, which occur when a DVT breaks off and travels to the lungs

Link Between Lung Cancer and Blood Clots

VTEs are a known complication of cancer in general — but particularly in lung cancer. One group of Italian doctors reviewed past studies that included well over 100,000 people with and without lung cancer. From the reports, they found pulmonary embolisms and DVTs were four to seven times more common in those with lung cancer than in the general population. Those same past studies also showed that VTEs occurred in as many as 13.8 percent of people with lung cancer.

One cause of VTEs is hypercoagulation (excessive blood clotting), which is observed in people with cancer. Hypercoagulation happens when someone has high levels of blood-clotting proteins. It's common in people with cancer.

People aged 65 years and older — which represents most people with lung cancer — are more likely to experience a VTE than are younger adults. Other medical conditions (like heart disease) that increase someone’s risk of blood clots are more common in this age group — and they often occur along with lung cancer.

Certain cancer treatments have also been associated with an increased risk of blood clots. VTEs are most common among people receiving chemotherapy. Those who have undergone lung cancer surgery are at risk for a DVT.

Risk Factors for Blood Clots

People with lung cancer are at a higher risk for VTEs, but there are also other factors that can increase your likelihood of getting a VTE.

Those factors include being:

• Overweight or obese
• 40 years old and older
• Inactive (sitting or laying down for long periods)
• Someone who smokes
• Pregnant

Hormone-based medications such as birth control pills can also increase a person’s risk of developing blood clots. In addition, there are several biological risk factors — genetic defects or a family history of blood clots — that impact the proteins involved in blood clotting.

Symptoms of Blood Clots

A VTE can be life-threatening and should be diagnosed as soon as possible. Symptoms to watch out for include:

• Shortness of breath
• Chest pain
• Swelling or tenderness in the limbs
• Increased heart rate
• Dizziness or feeling light-headed

If you notice some or all of these symptoms, seek immediate help from your health care provider. When you communicate promptly with your cancer care team during therapy and follow-up visits, your preventative treatment can start as soon as possible. That’s key, as early action helps to improve your outcomes.

Managing Risk of Blood Clots With Lung Cancer

The risk of a VTE cannot be completely eliminated. That means it is very important to consult with your health care provider about how to reduce your risk of blood clots. Medications called anticoagulants (blood thinners) may be used to reduce your risk of blood clots. If you are undergoing surgery for lung cancer, your doctor may prescribe anticoagulants to reduce your chance of developing blood clots following the operation. While you recover, your doctor may recommend wearing compression stockings to help prevent blood clots from forming in your legs.

People with lung cancer also should be proactive in lowering their risk for complications that come from blood clots treatments. For example, if you take blood thinners to manage your blood clots, prevent cuts as much as possible. Even a minor injury may lead to excessive bleeding. Also, avoid taking common anti-inflammatory medications for headaches and pain as these may further thin your blood.

Talk With Others Who Understand

On MyLungCancerTeam, the social network for people with lung cancer and their loved ones, more than 5,500 members and their loved ones come together to ask questions, give advice, and share their stories with others who understand life with the condition.

Are you or a loved one dealing with blood clots and lung cancer? Share your experience in the comments below, or start a conversation by posting on your Activities page.