What is the main cause of Superior Vena Cava (SVC) syndrome?

From the Guidelines

The main cause of Superior Vena Cava (SVC) syndrome is malignancies, with lung cancer being the most common cause, accounting for 72% of cases.

Causes of SVC Syndrome

• Malignancies, particularly lung cancer, are the primary cause of SVC syndrome, with 22% due to small cell lung cancer (SCLC) and 50% due to non-small cell lung cancer (NSCLC) 1
• Other causes include invasion or compression of the SVC by a mass in the right lung, lymph nodes, mediastinal structures, or thrombosis within the SVC 1 ### Pathophysiology
• Obstruction of the SVC leads to increased venous pressure, causing blood to flow through smaller collaterals to the azygos vein or inferior vena cava 1
• This results in symptoms such as neck swelling, swelling of one or both arms, and swelling of the face and eyelids, as well as dyspnea, headache, and hoarseness of the voice 1 ### Diagnosis and Management
• Definitive diagnosis by histologic or cytologic methods is recommended before treatment is started 2
• Treatment options include chemotherapy for SCLC, radiation therapy and/or stent insertion for NSCLC, and vascular stents for patients who fail to respond to chemotherapy or radiation therapy 3

From the Research

Causes of Superior Vena Cava (SVC) Syndrome

The main cause of Superior Vena Cava (SVC) syndrome is:

• Malignant disease, with lung cancer being the most common cause 4, 5, 6, 7
• Obstruction of the SVC by invasion, extrinsic compression by adjacent pathologic processes, or by internal thrombus 4, 8, 5
• Benign conditions, including sclerosing mediastinitis, which account for 15-20% of cases 7
• Central venous catheters, which represent an etiology of increasing importance 6

Mechanisms of SVC Syndrome

The syndrome is caused by:

• Compression, invasion, and/or thrombosis of the superior vena cava and/or the brachiocephalic veins 8
• Impaired venous return due to stenosis of the SVC 5
• External compression of the SVC, direct invasion, internal thrombus or embolization 5

Clinical Presentation

Symptoms of SVC syndrome include:

• Edema of the face and neck, edema of the upper limbs, superficial precordial vein distension due to collateral circulation 4, 5
• Hoarseness, cough, dyspnea, syncope, headache, and dizziness 5
• Increased venous pressure resulting in objective findings and subjective symptoms 4, 5