Blood Clots and Cancer: Understanding the Risks Beyond the Diagnosis

Because cancer touches so many individuals, most are aware of the diverse set of side-effects that come with this terrible disease. However, a common risk factor many might not consider to be linked with cancer is that of blood clots and cardiovascular events like heart attacks. However, since recent studies have shown such a correlation, it’s important to understand what all is entailed, why it happens, and what can be done to help cancer patients worry about one less thing during a particularly difficult life event.


The basics of blood clots

In general, blood clotting, also known as coagulation, is a good thing; in this process, platelets bond with proteins in plasma to prevent excessive bleeding.[1] While the body’s ability to protect an injured blood vessel is crucial, clots can also form on the inside of veins and arteries and won’t dissolve naturally, which restricts blood flow.[2]

Two of the major threats posed by abnormal clots in veins are deep vein thrombosis (DVT) and pulmonary embolisms (PE). DVT occurs when a clot forms in one of the major veins in the body, typically in the leg, though it can also occur in the arm or pelvis.[3] On some occasions, the clot may detach and travel to the lungs, causing pulmonary embolism, which can be especially dangerous.[4]

Additionally, clots in the arteries can restrict blood from flowing to the heart, leading to cardiovascular events like cardiac arrest. A blocked blood vessel that restricts blood supply to the brain can lead to a stroke.[5]


Why does this happen to cancer patients?

One research team found that the risk of suffering a stroke or heart attack was doubled for cancer patients during the first six months following their diagnosis.[6] Though the reasons for blood clot development vary, one of the causes in individuals diagnosed with cancer is invasive procedures patients must undergo during treatment.[7] Such procedures can dislodge a clot, moving it to the lung and causing a pulmonary embolism.[8] Additionally, tumors can release enzymes and proteins that affect coagulation and platelet function, which can in turn influence clot formation.[9] Finally, cancer therapies and drugs can also increase clotting risk.[10]


What can be done to prevent clots and cardiovascular events?

After a cancer diagnosis, other health concerns tend to take a backseat.[11] However, physicians need to address all the interconnected risks that can come with cancer in order to better treat their patients. Additionally, since the risk of blood clot development varies based on the type of cancer a patient has, advocating lung, stomach, and pancreatic cancer patients (which face the highest risk of strokes and heart attacks) special attention to their blood-health is critical.[12]

If patients are cognizant of the risks as well, taking the time to talk to their doctor and learn the symptoms of a clot, their increased awareness could save their life. Remember that pain, swelling, discoloration in the leg can be signs of deep vein thrombosis, while shortness of breath, chest pain, and unexplained rapid heart rate can be signs of pulmonary embolism.[13]


While there is no denying the physical and emotional stress a simple diagnosis can put upon the body, it is important to remember that other factors may be at play, and shouldn’t be forgotten. Medical staff need to be prepared to warn, monitor, and support cancer patients when it comes to blood clotting risks so as to hopefully create a better chance for a cure.

[1] “Blood Clots,” American Society of Hematology, n.d.,

[2] Ibid

[3] Ibid

[4] Ibid

[5] Nichols, Hannah, “The top 10 leading causes of death in the United States,”, Feb 23, 2017,

[6] Boggs, Will, “Increased risk of heart attack, stroke, soon after cancer diagnosis,”, Aug. 15, 2017,

[7] “Heart Attack, Stroke Risk May Be Elevated Following Cancer Diagnosis,” National Cancer Institute, Aug. 25, 2017,

[8] Ibid

[9] Ibid

[10] Ibid

[11] “Heart Attack, Stroke Risk”

[12] Mundell, E.J., “Heart Risks May Rise After Cancer Diagnosis,”, Aug. 15, 2017,

[13] “I have cancer: What do I need to know?” Clot Connection, n.d.,