SVC Syndrome (Superior Vena Cava Syndrome)

Symptoms, Causes, and Treatment of SVC Syndrome

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What is superior vena cava syndrome (SVC syndrome)?. Troels Graugaard/Vetta/Getty Images

Superior vena cava syndrome (SVC syndrome) is a set of symptoms that result when blood flow through the superior vena cava (the large blood vessel that returns blood from the upper body back to the heart) is blocked. This syndrome is a complication that occurs in 2 to 4 percent of people living with lung cancer, and in some cases is the first symptom that leads to the diagnosis.


The symptoms of SVC syndrome are caused by the buildup of pressure in the superior vena cava above the blockage and may include:

  • Swelling of the face, arms, or chest wall
  • Difficulty breathing (dyspnea)
  • Widening of the veins in the neck and chest
  • Cough and/or coughing up blood (hemoptysis)
  • Headache
  • Chest pain
  • Hoarseness
  • Difficulty swallowing (dysphasia)
  • Bluish tinge to the skin of the face or upper body (cyanosis)

When It's an Emergency

Superior vena cava syndrome may occur gradually in many patients, but can be a cancer-related medical emergency in some situations. If the obstruction of the superior vena cava occurs rapidly, there may not be time for other blood vessels (called collateral blood vessels or circulation) to accommodate the increased blood flow that takes place. Most worrisome is lung-cancer-induced SVC syndrome which causes obstruction of the trachea - the airway that travels from the nose to the large bronchi which enter the lung.

If you are experiencing any of these symptoms it's important to make an appointment to see your doctor right away. Studies tell us that many people with SVC syndrome wait too long before seeking medical attention. And even if you feel it is related to your cancer, it's important to talk to your doctor. Most of the people who die with SVC die from their cancer - NOT SVC syndrome. In addition, there may be medical conditions aside from cancer that are causing this problem.


The most common cause of SVC syndrome today is compression of the superior vena cava (SVC) by a cancerous tumor. The superior vena cava is a soft-walled vein and can be easily compressed by tumors growing nearby. Lung cancers, especially those growing in the right upper lung, are the most common cause, followed by lymphomas. The sread of other tumors, such as breast cancer to lymph nodes in the mediastinum (the area of the chest between the lungs) can also be responsible. Less common causes include blood clots within the SVC (often secondary to central intravenous lines or pacemaker wires) or infections like tuberculosis.


SVC syndrome is often suspected by the signs and symptoms noted above. Radiological studies such as a chest x-ray or CT scan may show a tumor or signs suggestive of SVC syndrome. Other tests, such as an MRI, ultrasound, or venography (a test done using a dye to x-ray veins) may be recommended as well. If your doctor suspects a cancer is causing your symptoms (and you are otherwise stable medically), further tests are then needed to diagnose the cancer before treatment is started.  Learn more about how lung cancer is diagnosed.


The treatment of SVC syndrome depends in large part upon the cause. If symptoms are due to a tumor pushing on the superior vena cava, methods to treat the tumor such as chemotherapy and radiation therapy are often used. Depending on the severity of your symptoms, a stent may be placed to hold the superior vena cava open. Blood thinners may be used to prevent clotting. In rare cases, surgery to bypass the obstruction may be needed.


The prognosis of SVC syndrome is variable and depends on the underlying cause.

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