To lower the chance of a pulmonary embolism (a blood clot in the lung) during cancer, discuss your clot risk with your oncology team. Depending on your situation, prevention may include a prescribed blood thinner, regular movement as you are able, and clot-prevention measures during hospital stays or surgery. Blood thinners are not right for everyone, because they can cause bleeding.
Why is pulmonary embolism prevention important in cancer?
A pulmonary embolism (PE) occurs when a blood clot blocks an artery in the lungs. The clot often begins as a deep vein thrombosis (DVT), a blood clot in a deep vein, usually in the leg or pelvis. If part of the clot breaks away and travels to the lungs, it can reduce blood flow and oxygen delivery.
Cancer can increase the likelihood of blood clots because of the disease itself and certain treatments. Preventing clots before they form is therefore an important part of care for people who have an elevated risk. According to the Centers for Disease Control and Prevention (CDC), cancer and treatments such as chemotherapy, surgery, hormonal therapy, and hospitalization are associated with an increased risk of blood clots.
Who with cancer has a higher risk of pulmonary embolism?
The chance of developing a clot differs from person to person. Your cancer type, treatment plan, medical history, and ability to move around all help determine which prevention measures may be appropriate.
Factors that can increase the risk of a blood clot include:
- Certain cancers: Pancreatic, stomach, brain, lung, kidney, and some blood cancers are associated with a higher risk.
- Cancer treatment: Some chemotherapy and hormonal treatments can increase clot risk.
- Recent surgery or hospitalization: Surgical procedures and reduced movement during recovery can contribute to clot formation.
- Limited mobility: Prolonged bed rest, sitting for long periods, or difficulty walking can slow blood flow.
- A previous blood clot: A personal or family history of blood clots may affect your risk assessment.
- Other health factors: Older age, obesity, smoking, certain chronic illnesses, and inherited clotting conditions may add to the risk.
- A central venous catheter: A tube placed in a large vein to deliver cancer treatment can be associated with a clot in that vein.
Having one or more of these factors does not mean that you will develop a pulmonary embolism. It means that your healthcare team may need to consider prevention more carefully, particularly when your treatment or mobility changes.
How can your cancer team assess and reduce your risk?
Ask your oncologist to review your risk of blood clots when you begin treatment, before surgery, during a hospital stay, and whenever your health or ability to move changes significantly. Risk assessment may be repeated throughout treatment because the factors affecting clot risk can change over time.
Your team may consider your cancer type, current medicines, previous clots, planned procedures, mobility, blood test results, and the possibility of bleeding. A risk-assessment tool may also help clinicians identify people who could benefit from preventive medication.
The American Society of Clinical Oncology (ASCO) clinical practice guideline recommends individualized decisions about preventive anticoagulation. Routine blood-thinning medication is not recommended for every person with cancer who is being treated as an outpatient.
Can blood thinners prevent pulmonary embolism in cancer patients?
Yes. Preventive anticoagulants, often called blood thinners, can reduce the chance of certain blood clots forming. They are an important option for selected people with cancer who have a higher risk of clotting and an acceptable risk of bleeding.
Which preventive medicines might be prescribed?
Depending on your circumstances, your healthcare professional may consider:
- Low-molecular-weight heparin (LMWH): An anticoagulant usually given by injection under the skin.
- Apixaban or rivaroxaban: Oral anticoagulants that may be offered to selected high-risk adults receiving systemic cancer treatment.
- Other anticoagulants: The appropriate choice depends on the clinical setting, the reason for prevention, and individual medical factors.
Before prescribing a medicine, your healthcare team considers whether its potential benefit outweighs the risk of bleeding. They may also review your kidney function, platelet count, other medicines, planned procedures, and cancer-related bleeding risks. Drug interactions can affect which option is suitable.
For selected high-risk outpatients starting a new systemic chemotherapy regimen, ASCO guidance allows clinicians to consider apixaban, rivaroxaban, or LMWH when there are no significant bleeding risks or problematic drug interactions. The decision should include a discussion of benefits, risks, cost, and how long prevention may be needed.
Why should you avoid taking blood thinners without medical advice?
Anticoagulants can cause serious bleeding. Taking aspirin, another person's prescription medicine, or leftover anticoagulants without guidance may expose you to harm without providing the right protection. Do not start, stop, or change a prescribed anticoagulant dose without discussing it with your healthcare professional.
If you already take a blood thinner because of a previous clot or another medical condition, follow your prescribed plan. Ask your healthcare team what to do if you miss a dose, develop bleeding, or need surgery or another procedure.
How is blood clot prevention handled during cancer surgery or hospitalization?
Surgery and hospital stays can increase clot risk, particularly when illness or recovery limits movement. Your surgical and oncology teams should assess whether you need preventive medication, mechanical measures, or both. The plan should account for the timing of surgery, your bleeding risk, and your expected recovery.
ASCO's guidance recommends preventive anticoagulation for patients undergoing major cancer surgery unless bleeding or another contraindication makes it unsuitable. Prevention commonly continues for at least 7 to 10 days after major surgery. Some people undergoing major abdominal or pelvic cancer surgery, particularly those with additional risk factors, may benefit from extended prevention for up to four weeks.
During hospitalization, preventive anticoagulation may also be appropriate for people with active cancer who have an acute medical illness or reduced mobility. However, it is not automatically required for every hospital visit or brief chemotherapy infusion.
What about compression stockings and other mechanical measures?
Compression stockings and intermittent pneumatic compression devices can help support blood flow in selected situations. These measures may be used alongside medication, particularly around surgery or when movement is restricted.
Ask your healthcare team whether compression is appropriate for you. Mechanical methods should not replace preventive anticoagulants when medication is suitable and indicated, although they may be used alone when anticoagulants cannot safely be given.
Can movement and daily habits help prevent pulmonary embolism?
Staying as active as your health permits is a practical way to support blood circulation. Movement alone cannot eliminate clot risk during cancer treatment, but it can form part of a broader prevention plan.
- Walk regularly when able. Short walks around your home or hospital room may help keep you moving during treatment and recovery.
- Move your legs while sitting. Gentle ankle movements and bending and straightening your legs can be useful when you cannot get up often.
- Break up long periods of sitting. During long journeys or other extended periods of sitting, change position and move around when it is safe to do so.
- Follow your postoperative mobility plan. Ask when you can get out of bed and walk after surgery, especially if you have pain, weakness, or movement restrictions.
- Discuss a suitable activity level. If fatigue, pain, breathlessness, or treatment side effects make exercise difficult, ask your healthcare team how to move safely.
- Address other health risks. If you smoke, seek support to stop. Discuss weight management and other health conditions with your healthcare professional when appropriate.
MedlinePlus, a health information service of the US National Library of Medicine, identifies early movement after surgery, leg movement during prolonged sitting, appropriate compression stockings, and prescribed anticoagulants as possible measures for preventing blood clots and pulmonary embolism.
Do not force yourself to exercise when you have been advised to restrict activity. Your plan should match your treatment, surgical recovery, strength, and overall health. If you are at high risk, movement and lifestyle changes may need to be combined with medical prevention.
What symptoms should you recognize even when taking preventive measures?
Prevention reduces risk but cannot prevent every clot. Learning the warning signs can help you seek care promptly if a clot develops.
Possible signs of a deep vein thrombosis include:
- Swelling in one leg or arm.
- Pain or tenderness that is not explained by an injury.
- Skin that feels warmer than usual or appears red or discolored.
Contact your cancer team promptly if you develop these symptoms. Do not wait for all the symptoms to appear before seeking advice.
Symptoms that may occur with a pulmonary embolism include:
- Sudden or unexplained difficulty breathing.
- Chest pain that worsens when taking a deep breath or coughing.
- A rapid or irregular heartbeat.
- Coughing up blood.
- Lightheadedness, fainting, or collapse.
Seek emergency medical attention immediately if you experience symptoms that may indicate a pulmonary embolism, particularly sudden breathing difficulty, chest pain, coughing up blood, or fainting. Do not wait for a routine oncology appointment or assume that symptoms are caused by cancer treatment.
How can you make clot prevention part of your cancer care plan?
A useful prevention plan starts with a conversation with your oncology team. Before treatment or surgery, ask whether your personal risk has been assessed and whether you need medication or mechanical prevention. If you are hospitalized, ask what measures will be used to reduce clot risk and when you should begin moving around.
Keep an updated list of your medicines and tell each healthcare professional about previous blood clots, family history, and any bleeding problems. If you take an anticoagulant, understand its prescribed dose, duration, important interactions, and what to do if you miss a dose or notice bleeding.
Finally, know how to contact your cancer team promptly about new leg or arm swelling and how to obtain emergency care for possible pulmonary embolism symptoms. An individualized plan that combines appropriate medical prevention, safe movement, and prompt evaluation of warning signs offers a practical approach to lowering risk throughout cancer care.