A pulmonary embolism (PE) occurs when a blood clot, often originating in a deep vein, travels to the lungs and obstructs blood flow. This life-threatening condition is notably elevated in individuals with cancer.
The Link Between Cancer and Blood Clot Formation
Cancer significantly increases the likelihood of developing blood clots, with the risk of venous thromboembolism (VTE), including PE, being about four times higher in cancer patients. This heightened risk stems from the cancer itself, various treatments, and patient characteristics. Certain cancer types, such as pancreatic, brain, ovarian, and lung cancers, carry a particularly elevated risk.
Cancer cells can directly influence the body’s clotting system. They release substances that activate the coagulation cascade, promoting clot formation. This creates a hypercoagulable state, meaning the blood is more prone to clotting. Some cancer cells can also stimulate the body to produce clotting factors, making the blood “sticky”.
Cancer treatments also contribute to this risk. Chemotherapy, hormone therapy, and certain immunotherapies can increase the likelihood of clots. Surgery, a common cancer intervention, is a leading cause of blood clots. Cancer surgery doubles the risk of postoperative deep vein thrombosis and triples the risk of fatal PE compared to similar procedures in non-cancer patients. Reduced mobility due to illness or hospitalization also leads to blood pooling in veins, increasing clot formation.
Identifying Blood Clot Symptoms
Recognizing PE symptoms is important for cancer patients, as prompt identification can be life-saving. Common symptoms often appear suddenly and may include shortness of breath, which can occur even at rest and worsen with physical activity. Chest pain is another frequent symptom, often described as sharp and intensifying with deep breaths, coughing, bending, or leaning. This pain can sometimes be mistaken for a heart attack.
A persistent cough, sometimes producing bloody mucus, can also signal a PE. Other signs include a rapid or irregular heartbeat, lightheadedness or dizziness, and excessive sweating. Swelling, pain, warmth, or tenderness, typically in one leg or arm, can indicate a deep vein thrombosis (DVT), a precursor to PE. Symptoms vary in intensity, but urgent medical attention is advised for any unexplained shortness of breath, chest pain, or fainting.
Diagnostic Methods and Treatment Strategies
Diagnosing pulmonary embolism in cancer patients often involves imaging and blood tests. While an elevated D-dimer blood test can suggest a clot, its results can be non-specific in cancer patients, as D-dimer levels can be high due to the cancer itself, even without a clot. Therefore, imaging tests are often needed for confirmation.
Computed tomography pulmonary angiography (CTPA) is a common imaging test that provides detailed images of the pulmonary arteries to detect blockages. In some cases, a ventilation-perfusion (V/Q) scan, which assesses airflow and blood flow in the lungs, may be used. Due to the higher prevalence and potentially worse outcomes of VTE in cancer patients, healthcare providers often have a low threshold for diagnostic workups.
Once a PE is diagnosed, treatment focuses on preventing new clots and stopping existing ones from growing. Anticoagulant medications, or blood thinners, are the primary therapy. These medications, such as low-molecular-weight heparin (LMWH) or direct oral anticoagulants (DOACs), are typically prescribed for at least three to six months, and often longer, as long as the cancer is active. In severe cases, particularly if the patient’s condition is unstable, thrombolytic therapy (clot-dissolving medications) or procedures to physically remove the clot may be considered. Treatment plans are individualized, taking into account the type of cancer, its stage, and the patient’s overall health and risk of bleeding.
Reducing Risk and Long-Term Care
Preventative measures and ongoing management reduce the risk of blood clots in cancer patients. Maintaining physical activity and mobility, even light movement, promotes blood circulation and deters clot formation. Staying well-hydrated is also beneficial for blood flow. For individuals at high risk, particularly during hospitalization or certain outpatient treatments, prophylactic anticoagulants, such as low molecular weight heparin, may be recommended to prevent clots.
Long-term care after a PE diagnosis involves consistent adherence to prescribed anticoagulant medications, usually continued as long as the patient is undergoing cancer treatment. Regular monitoring by healthcare professionals is also necessary to assess medication effectiveness, adjust dosages, and monitor for any potential side effects like bruising or bleeding. While anxiety about recurrence is common, consistent use of these medications significantly reduces the chance of another PE, with fewer than 10% of patients experiencing new or recurrent clots when adhering to their prescribed regimen.