SUPERIOR VENA CAVA SYNDROME
Superior vena
cava (SVC) syndrome is caused by extrinsic compression or internal thrombosis
of the SVC, which compromises the venous drainage from the head and upper
extremities. Lung cancer is responsible for the large majority of SVC syndrome
in adults older than age 40 years. Lymphoma is the most common cause in younger
individuals. Patients complain of a sensation of fullness in the head, cough,
or dyspnea. They may experience lightheadedness, especially when bending over,
or have edema and swelling in the head, neck, and arms. Edema of the larynx or
pharynx may result in stridor, and cerebral edema may result in head-aches or
confusion.
Physical findings include dilated neck veins and
subcutaneous veins of the chest that persist with the patient in an upright
position. Facial edema and a plethoric appearance may be present. Computed
tomography chest scans with contrast injected through the arm veins show the
mass with narrowing or obstruction of the SVC and the extensive venous
collateral circulation of subcutaneous and mediastinal veins. If the SVC
syndrome is caused by a benign condition such as fibrosing mediastinitis, then a
lung mass will not be identified.
Small cell carcinoma is the classic histology to cause
SVC syndrome, but any histologic type may do so. Although SVC syndrome is a
serious condition, it is not generally an emergency situation. Accordingly, a
tissue diagnosis should be obtained before treatment begins. It is important to
know if it is caused by lymphoma, small cell carcinoma, or non–small cell lung
cancer before the appropriate treatment is instituted. SVC syndrome may
occasionally be caused by other tumors (e.g., breast cancer, germ cell tumor), fibrosing mediastinitis, or an
infectious process (rarely). Bronchoscopy has a high diagnostic rate when SVC
syndrome is caused by lung cancer. If bronchoscopy results are negative, then
mediastinoscopy is the next logical procedure in most cases.
Treatment of patients with SVC syndrome should include
stenting of the SVC early on in the process. This treatment quickly relieves
the obstruction in more than 90% of cases. Chemotherapy alone as initial treatment is indicated
for cases caused by small cell carcinoma or lymphoma, and radiotherapy or
combined chemoradiotherapy is used for non–small cell lung cancer. Treatment
should rarely be given without a tissue diagnosis. In patients with SVC
syndrome caused by lung cancer, the long-term prognosis is related to the
histologic type and stage of the disease at the time of initial diagnosis.
