The superior vena cava is a major vein that leads to the heart. The heart is divided into four parts. The right and left atrium make up the top parts of the heart and the right and left ventricle make up the bottom parts of the heart. The right atrium of the heart receives blood from two major veins:
Different conditions can slow the flow of blood through the superior vena cava. These include a tumor in the chest, nearby lymph nodes that are swollen (from cancer), or a blood clot in the superior vena cava. The vein may become completely blocked. Sometimes, smaller veins in the area become larger and take over for the superior vena cava if it is blocked, but this takes time. Superior vena cava syndrome (SVCS) is the group of symptoms that occur when this vein is partly blocked.
Superior vena cava syndrome (SVCS) is usually caused by cancer. In adults, SVCS is most common in the following types of cancer:
Less common causes of SVCS include:
The symptoms of SVCS are more severe if the vein becomes blocked quickly. This is because the other veins in the area do not have time to widen and take over the blood flow that cannot pass through the superior vena cava.
The most common symptoms are:
Less common symptoms include the following:
The following tests may be done to diagnose SVCS and find the blockage:
It is important to find out the cause of SVCS before starting treatment. The type of cancer can affect the type of treatment needed. Unless the airway is blocked or the brain is swelling, waiting to start treatment while a diagnosis is made usually causes no problem in adults. If doctors think lung cancer is causing the problem, a sputum sample may be taken and a biopsy may be done.
Treatment for SCVS caused by cancer depends on the following:
The following may be used to relieve symptoms and keep the patient comfortable:
Chemotherapy is the usual treatment for tumors that respond to anticancer drugs, including small cell lung cancer and lymphoma. Chemotherapy uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
If the blockage of the superior vena cava is caused by a tumor that does not usually respond to chemotherapy, radiation therapy may be given. Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. External radiation therapy uses a machine outside the body to send radiation toward the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
SVCS may occur when a thrombus (blood clot) forms in a partly blocked vein. Thrombolysis is a way to break up and remove blood clots. This may done by a thrombectomy. Thrombectomy is surgery to remove the blood clot or the use of a device inserted into the vein to remove the blood clot. This may be done with or without the use of drugs to break up the clot.
If the superior vena cava is partly blocked by the tumor, an expandable stent (tube) may be placed inside the superior vena cava to help keep it open and allow blood to pass through. This helps most patients. Drugs to keep more blood clots from forming may also be used.
Surgery to bypass (go around) the blocked part of the vein is sometimes used for cancer patients, but is used more often for patients without cancer.
Superior vena cava syndrome is serious and the symptoms can be upsetting for the patient and family. It is important that patients and family members ask questions about superior vena cava syndrome and how to treat it. This can help relieve anxiety about symptoms such as swelling, trouble swallowing, coughing, and hoarseness.