Superior vena cava obstruction (SVCO)

Superior vena cava obstruction (SVCO) is a blockage of a large vein in the chest called the superior vena cava (SVC).

What is a superior vena cava obstruction (SVCO)?

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

Superior vena cava obstruction (SVCO) happens when something blocks the blood from flowing along the SVC. The walls of the SVC are thin. This 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.

These are other possible causes:

  • Other cancers affecting the lymph nodes in the chest. These include lymphomas or testicular, breastbowel or gullet (oesophagus) cancers.
  • 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. They 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 get worse when you lean forward or bend over
  • facial swelling, with a dark red look to your complexion
  • changes in your eyesight
  • swollen neck, arms and hands
  • visible swollen blue veins on the chest
  • feeling dizzy.

It is important to let your nurse or doctor know straight away if you have any of these symptoms. The symptoms can be distressing but they can usually be controlled quickly.

Managing symptoms of SVCO

The symptoms of SVCO can be distressing, but 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 breathless, sitting in an upright position might be more comfortable.


Your doctor may give you 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

The most common test for SVCO is a chest x-ray. This is usually followed by other tests, such as

If someone is diagnosed with SVCO but has not been diagnosed with cancer, they will have tests to find out the cause of the 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. This lets the blood 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 have 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 is usually used on its own, 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 called external radiotherapy. Radiotherapy is given as a short course. It 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.