Assessing malignancy-related superior vena cava obstruction in palliative care
Malignancy-related superior vena cava (SVC) obstruction is caused by extrinsic compression or intraluminal invasion. Primary bronchial carcinomas and lymphomas are the most common underlying malignancies. Obstruction can also be due to thrombosis associated with central venous lines (commonly used to administer chemotherapy) and the hypercoagulable state of cancer.
Superior vena cava obstruction commonly presents with breathlessness and cough. Other symptoms include headache, hoarseness and dizziness. Symptom severity depends on the size and onset of obstruction. Approximately 5% of patients with superior vena cava obstruction present with life-threatening features. Features of life-threatening superior vena cava obstruction are confusion or obtundation, stridor, or signs of significant haemodynamic compromise (eg syncope, acute kidney injury, hypotension).
The most common examination finding in patients with superior vena cava obstruction is facial oedema. Other signs are arm oedema, distended neck and chest veins, and facial plethora—these are exacerbated by raising the patient’s arms above their head. Chest X-ray is usually abnormal, showing a mass that widens the mediastinum. Chest computed tomography (CT) with contrast is diagnostic, and provides information on the cancer as well as determining whether the cause is extrinsic compression or thrombosis. However, performing a CT requires the patient to lie flat, which can exacerbate symptoms.