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 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 flow along the SVC. Because the walls of the SVC are thin, they can easily become squashed (compressed).


Causes of SVCO

Most cases of SVCO are caused by lung cancer. The cancer may press directly on the SVC. Or it may spread to the lymph nodes (glands) nearby, which become swollen.

These are other possible causes:

Symptoms of SVCO

Symptoms of SVCO are caused by the blood flow to the heart being blocked. This causes increased pressure in the head, neck and arms.

Symptoms can develop quickly over a few days or over a few weeks. The first symptom is usually 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 changes to your complexion
  • changes in your eyesight
  • a swollen neck
  • swollen arms and hands
  • visible swollen blue veins on the chest
  • feeling dizzy.

It is important to tell your nurse or doctor straight away if you have any of these symptoms. SVCO needs to be treated 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 have drugs such as:

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

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 you have had other treatments.

Diagnosing SVCO

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

If you are diagnosed with SVCO but you do not have cancer, you 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 how severe the symptoms are and the type of cancer you have.


A stent is a small tube that can be put into the SVC 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.

You may have a stent as the first treatment for SVCO. This is because it relieves symptoms quickly. You may also have a stent if SVCO has come back after radiotherapy or chemotherapy.

Stents may not be suitable for people who have a blood clot. Not everyone will be able to have this treatment. 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.

Radiotherapy rays are directed at the tumour from outside the body. This is called external radiotherapy. You sometimes have a short course of radiotherapy 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, for example with lymphoma or small cell lung cancer (SCLC). 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, can be used to treat SVCO caused by blood clots.

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 about SVCO

SVCO can be frightening, as it usually involves:

  • swelling
  • breathlessness
  • a tightening sensation around the chest, head and neck areas.

This may cause many different emotions, including anger, resentment, guilt, anxiety and fear. These are all normal reactions that many people go through.

Everyone has their own way of coping with difficult situations. You may find it helpful to talk to family or friends. Or you may prefer to seek help from people outside your 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.

Macmillan is also here to support you. If you would like to talk, you can:

About our information

  • References

    Below is a sample of the sources used in our superior vena cava obstruction information. If you would like more information about the sources we use, please contact us at

    National Institute for Health and Care Excellence (NICE). Lung cancer – Diagnosis and management. Clinical guideline 2019.

    Scottish Palliative Care Guidelines. Superior Vena Cava Obstruction. NHSScotland 2019.

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

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We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

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Date reviewed

Reviewed: 01 November 2020
Next review: 01 November 2023

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.