Superior vena cava obstruction (SVCO)

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

SVCO is usually caused by lung cancer near to this 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. They can 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. It may include having a small tube (a stent) put into the vein to keep it open, radiotherapy or chemotherapy.

What is a superior vena cava obstruction (SVCO)?

The superior vena cava (SVC) is a large vein that carries blood from the upper half of the body straight to the heart. It lies in the middle of the chest, behind the breast bone (sternum).

Superior vena cava obstruction (SVCO) happens when something blocks the blood from flowing along the SVC. The walls of the SVC are thin, which means 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 happen after having a small plastic tube (central line) put into the vein, to give treatments such as chemotherapy.

Symptoms of SVCO

Symptoms of SVCO are caused by the blood flow to the heart being blocked. Symptoms can develop quickly over a few weeks or even days. The first symptom is often feeling a 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 your complexion
  • visual disturbances
  • swollen neck
  • swollen arms and hands
  • visible swollen blue veins on the chest
  • dizziness.

It is important to let your nurse or doctor know straight away if you have any of these symptoms.

Managing symptoms of SVCO

Although the symptoms of SVCO can be distressing, they can usually be quickly controlled. 

You may be given oxygen to improve your breathing. You may also be given drugs, such as:

  • painkillers, to ease any pain
  • water tablets (diuretics) to get rid of extra fluid
  • sedatives, to help relax you.

Bed rest

Your doctor will usually advise bed rest, ideally with the head of the bed raised. If you are short of breath, sitting in an upright position might be more comfortable.


You may be given high doses of a steroid drug called dexamethasone. This will help reduce pressure and swelling around the blood vessel. It will also improve symptoms such as breathlessness. The dose will be reduced gradually after other treatments have been given.

Diagnosing SVCO

Treating SVCO

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


A stent is a small tube that can be put into the blood vessel to keep it open, allowing the blood to flow through. Your doctor will usually put it in using a local anaesthetic. They may give you a medicine to help you relax. The doctor uses x-ray images to guide the stent into the correct position.

A stent is often used as the first treatment for SVCO, as it relieves symptoms quickly. Stents can also be used if SVCO has come back after radiotherapy or chemotherapy. This treatment may not be suitable for people who have a blood clot. Not everyone will be fit enough to cope with it. Your doctor can tell you if it is suitable for you.


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 uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It is sometimes 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.

Drugs to treat blood clots

Drugs called anti-coagulants, such as heparin and warfarin, are used to treat blood clots and 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 a tightening sensation around your chest, head and neck area. This may cause many different emotions including anger, resentment, guilt, anxiety and fear. These are all normal reactions that can be part of the process many people go through.

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.