SUPERIOR VENA CAVA SYNDROME
Superior vena cava syndrome (SVCS) is a common occurrence in cancer patients and can lead to life-threatening complications such as cerebral or laryngeal edema. Although most commonly resulting from external compression of the vena cava by a tumor, SVCS can also stem from nonmalignant causes in cancer patients.
Etiology
Malignant causes
Primary intrathoracic malignancies are the cause of SVCS in approximately 87% to 97% of cases. The most frequent malignancy associated with the syndrome is lung cancer, followed by lymphomas and solid tumors that metastasize to the mediastinum.
Lung cancer SVCS develops in approximately 3% to 15% of patients with bronchogenic carcinoma, and it is four times more likely to occur in patients with right- versus left-sided lesions.
Metastatic disease Breast and testicular cancers are the most common metastatic malignancies causing SVCS, accounting for > 7% of cases. Metastatic disease to the thorax is responsible for SVCS in ~3% to 20% of patients.
Nonmalignant causes
Thrombosis The most common nonmalignant cause of SVCS in cancer patients is thrombosis secondary to venous access devices.
Other nonmalignant causes include cystic hygroma, substernal thyroid goiter, benign teratoma, dermoid cyst, thymoma, tuberculosis, histoplasmosis, actinomycosis, syphilis, pyogenic infections, radiation therapy, silicosis, and sarcoidosis. Some cases are idiopathic.
Signs and symptoms
Classic symptoms Patients with SVCS most often present with complaints of facial edema or erythema, dyspnea, cough, orthopnea, or arm and neck edema. These classic symptoms are seen most commonly in patients with complete obstruction, as opposed to those with mildly obstructive disease.
Other associated symptoms may include hoarseness, dysphagia, headaches, dizziness, syncope, lethargy, and chest pain. The symptoms may be worsened by positional changes, particularly bending forward, stooping, or lying down.
Common physical findings The most common physical findings include edema of the face, neck, or arms; dilatation of the veins of the upper body; and plethora or cyanosis of the face. Periorbital edema may be prominent.
Other physical findings include laryngeal or glossal edema, mental status changes, and pleural effusion (more commonly on the right side).
Diagnosis
It is important to establish the diagnosis and underlying etiology of SVCS, because some malignancies may be more amenable to specific treatment regimens than others. In the majority of cases, the diagnosis of SVCS is evident based on clinical examination alone.
The following diagnostic procedures may aid in establishing the diagnosis of SVCS and its etiology: chest x-ray, bronchoscopy, limited thoracotomy or thoracoscopy, contrast and radionuclide venography, Doppler ultrasonography, CT (especially contrast-enhanced spiral CT), and MRI.
Prognosis
The prognosis of SVCS depends on the etiology of the underlying obstruction. A review by Schraufnagel showed the average overall survival after the onset of SVCS to be 10 months, but there was wide variation (± 25 months) depending on the underlying disease, with an average survival of 7.6 months. This duration was not significantly different from the survival duration of 12.2 months in patients presenting with SVCS as the primary manifestation of the disease. Thoracic malignancy, the most common cause of SVCS, had a poor prognosis of < 5 months’ survival.
Treatment
Treatment includes radiotherapy, chemotherapy, thrombolytic therapy and anticoagulation, expandable wire stents, balloon angioplasty, and surgical bypass.
Most patients derive sufficient relief from obstructive symptoms when treated with medical adjuncts, such as diuretics and steroids (see section on “Adjunctive medical therapy”), so they can tolerate a workup to determine the etiology of SVCS. In some instances, it is appropriate to delay treatment for 1 to 2 days if necessary to establish a firm tissue diagnosis.
