Superior Vena Cava (SVC) Syndrome

Author: Marisa Healy, BSN RN

Content Contributor: Katherine Okonak, LSW

Last Reviewed: June 23, 2026

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What is superior vena cava syndrome (SVC)?

Your superior vena cava (SVC) is a large blood vessel that carries blood from your head and upper body to your heart. SVC syndrome happens when blood flow through the superior vena cava is blocked.

SVC syndrome is an oncologic (cancer) emergency, which is a serious health problem caused by the cancer itself or its treatment. Oncologic emergencies need to be treated right away.

What causes SVC syndrome?

SVC syndrome is often caused by a tumor or swollen lymph nodes pressing on your SVC. SVC syndrome is common in lung cancer, lymphoma, breast cancer, and other primary tumors that have spread to the chest. It can also be caused by blood clots in the SVC.

What are the symptoms of SVC syndrome?

Symptoms can happen slowly or quickly. If SVC syndrome is caused by cancer, symptoms often happen more slowly than if it is caused by blood clots. Symptoms can be:

Swelling of your face, arms, or upper chest.
Having a hard time breathing (dyspnea).
Widening of the veins in your neck and chest.
Cough and/or coughing up blood (hemoptysis).
Headache or a feeling of fullness in your head and ears.
Having a hard time swallowing (dysphagia).
A hoarse or strained voice.
Chest pain.
Blue or red-coloring to the skin of your face or upper body.
Changes to your vision.

How is it diagnosed and treated?

SVC syndrome is an oncologic emergency and needs to be treated right away. It can be diagnosed through a physical exam and chest X-ray, but you may need more imaging tests (CT/MRI/venography) to measure how much of your SVC is blocked.

SVC syndrome is treated based on the cause:

If SVC syndrome is caused by a tumor pressing on the SVC, chemotherapy or radiation therapy may be used to shrink the tumor. This helps the blood flow better. A stent may be put in the SVC to hold it open to let blood flow.
If a blood clot is causing SVC syndrome, blood thinners will be given.
Corticosteroids can be used to lessen swelling.
Diuretics may be used to decrease the amount of fluid in your body.

When should I call my provider?

If you are having any symptoms of SVC syndrome listed above, call your provider right away. If you are having a hard time breathing, call 911 or go to the emergency room right away.