Superior vena cava obstruction

The superior vena cava is a large vein in the chest. It carries blood from the body into the heart. Superior vena cava obstruction (SVCO) occurs when something blocks this blood flow.

SVCO is usually caused by lung cancer near the vein. The cancer may be pressing on the vein or it may have spread to the lymph nodes nearby, causing them to swell. It can also be caused by a blood clot blocking the vein. This can happen if you’re having treatment through a central line.

Symptoms of SVCO can develop quite quickly. These may include:

  • a feeling of fullness in your face when you bend over
  • breathlessness
  • headaches
  • swelling in the face, neck, arms, hands and veins on your chest
  • visual disturbances
  • dizziness.

These symptoms can be distressing but are usually controlled quickly. You may be given oxygen, painkillers, or steroids. Treatment for SVCO will vary from person to person, and may include radiotherapy, chemotherapy, or having a small tube (a stent) inserted into the vein to keep it open.

What is a superior vena cava obstruction?

The superior vena cava (SVC) is a large vein that carries blood from the body straight to the heart. It lies in the middle of the chest, behind the breast bone (sternum).
Superior vena cava obstruction (SVCO) occurs when something blocks the blood from flowing along the SVC. The walls of the SVC are thin, meaning they easily become squashed (compressed).


Causes of SVCO

Most cases of SVCO are caused by an underlying lung cancer. The cancer itself may be pressing directly on the SVC, or it may have spread to the lymph nodes (glands) nearby which become swollen.

Other possible causes are:

  • other cancers, such as lymphomas or testicular, breast, bowel or gullet (oesophagus) cancers affecting the lymph nodes in the chest
  • a blood clot forming in the vein and blocking the blood flow - this can result from having a small plastic tube (central line) threaded into the vein to give treatments such as chemotherapy.


How SVCO is diagnosed

SVCO often develops quite quickly over a few weeks or even days.

Symptoms are caused by the blood flow to the heart being obstructed. The first symptom is often a sensation of fullness in the face when you bend over. The other most common symptoms are:

  • breathlessness because of swelling around the windpipe (trachea)
  • headaches, which worsen on leaning forward or bending over
  • facial swelling with a dark red look to the complexion
  • visual disturbances
  • swollen neck
  • swollen arms and hands
  • visible swollen blue veins on the chest
  • dizziness.


How SVCO is diagnosed

Chest x-ray

The most common test for SVCO is a chest x-ray, which is usually followed by other tests such as an ultrasound, a CT or MRI scan.

If someone is diagnosed with SVCO but is not known to have cancer, tests will be done to establish the cause of the SVCO.


Treatment for SVCO

There are different ways of treating SVCO. The treatment you have will depend on different factors, including the type of cancer you have.

Radiotherapy

Radiotherapy uses high energy x-rays to destroy cancer cells while doing as little harm as possible to normal cells. It’s usually used alone, but it can be used in combination with other treatments, such as chemotherapy. Radiotherapy rays are directed at the tumour from outside the body - this is known as external radiotherapy. Radiotherapy is given as a short course and usually starts immediately after SVCO is diagnosed.

Chemotherapy

Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It’s occasionally used to treat SVCO where the tumours are sensitive to chemotherapy, such as lymphoma or small cell lung cancer. Chemotherapy can also be used to treat SVCO in breast cancer. 

Stent

A stent is a small tube that can be inserted into the blood vessel to keep it open, allowing the blood to flow through. The tube is put in under a general anaesthetic. The doctor uses x-ray images to guide the stent into the correct position. It can be used if doctors feel that radiotherapy or chemotherapy is unlikely to help, or if the SVCO has come back after radiotherapy or chemotherapy. It relieves most people’s symptoms within 72 hours. This treatment is not suitable for people who have a blood clot, and because it requires a tube to be inserted into the main vein in the chest, not everyone will be fit enough to cope with it.

Drugs to thin the blood

Drugs known as anti-coagulants, such as heparin and warfarin, dissolve blood clots and can therefore be used to treat SVCO that has been caused by a clot. If the blood clot is around a central line, it may be necessary to remove the line. In this situation, your doctors will discuss other cancer treatment options with you.


Your feelings

SVCO can be very frightening as it often involves swelling, feelings of breathlessness and choking. You may have many different emotions including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their condition.

Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is there if you need it. Our cancer support specialists can give you information about counselling in your area.


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