Cancer can significantly increase an individual’s risk of developing blood clots. This complication is a notable concern for patients, as blood clots are estimated to affect up to 20% of cancer patients at some point during their disease journey. Understanding this connection is important because blood clots represent the second leading cause of death in people with cancer, after the cancer itself.
The Link Between Cancer and Blood Clots
Cancer creates hypercoagulability, an increased tendency for blood to clot. Tumor cells play a direct role by releasing substances that activate the body’s clotting system. For example, they produce procoagulants like Tissue Factor and cancer procoagulant, along with microparticles that carry these activators, directly triggering clot formation.
Beyond direct effects, cancer induces inflammatory responses throughout the body. This inflammation further activates the coagulation cascade, making blood stickier and more prone to clotting. Certain types of cancer, such as those of the pancreas, stomach, lung, brain, and kidney, are particularly associated with a higher risk of blood clots.
Tumors can also contribute to clot formation by compressing nearby blood vessels, slowing blood flow and creating favorable conditions.
Cancer treatments themselves can also elevate the risk of blood clots. Major surgical procedures can injure blood vessels and reduce mobility, both promoting clotting. Chemotherapy agents can damage the inner lining of blood vessels, activating the clotting cascade. Hormone therapies, targeted therapies, and central venous catheters (tubes for treatment delivery) also increase clot susceptibility.
Types of Blood Clots Associated with Cancer
Deep vein thrombosis (DVT) and pulmonary embolism (PE) are the most common and serious blood clots in cancer patients. DVT involves a blood clot within a deep vein, most frequently in the legs or arms. These clots can partially or completely block blood flow in the affected vein.
A pulmonary embolism occurs when a DVT portion breaks away, travels through the bloodstream, and lodges in lung arteries, blocking blood supply.
Together, DVT and PE are known as venous thromboembolism (VTE), a significant health concern for cancer patients.
Recognizing Blood Clot Symptoms
Cancer patients and their caregivers should recognize blood clot signs. DVT symptoms in an arm or leg commonly include swelling, pain, or tenderness. The skin may appear red or discolored and feel warm. These symptoms can be subtle or absent in about half of individuals.
If a blood clot travels to the lungs, causing a pulmonary embolism (PE), symptoms can be sudden and severe. Common signs of a PE include sudden shortness of breath, which may worsen with physical activity, and chest pain. Chest pain is often sharp and worsens with deep breaths or coughing. Other indicators include a rapid or irregular heartbeat, lightheadedness, or coughing, sometimes with blood.
Seek immediate medical attention if any of these symptoms are observed. Early diagnosis and treatment prevent serious complications and improve outcomes for cancer patients.
Managing and Preventing Cancer-Related Blood Clots
Managing existing blood clots in cancer patients primarily involves anticoagulant medications, often called “blood thinners.” These medications prevent clots from growing and new ones from forming, allowing the body to gradually break down existing clots. Common anticoagulants include low molecular weight heparin (LMWH), administered by injection, and direct oral anticoagulants (DOACs), taken as pills. Treatment typically ranges from three to six months, but may be extended depending on the individual’s situation.
Preventive measures are also important to reduce the risk of blood clots in cancer patients. For higher-risk patients, especially during hospitalization or certain treatments, prophylactic anticoagulants may be prescribed. Mechanical methods, such as elastic compression stockings or intermittent pneumatic compression devices, can also improve leg blood flow.
Lifestyle adjustments can further contribute to prevention. Maintaining physical activity, even short walks or simple leg exercises, helps promote circulation. Staying well-hydrated also reduces blood clot risk. Patients should discuss individual risk factors and preventive strategies with their cancer care team for a personalized approach.