Radiation
Indications.
The majority of cases of SVCS are
caused by malignancy; thus, most patients receive radi-
ation treatment at some point in their illness. Emer-
gency radiation treatment has been administered to
some patients with life-threatening cerebral or laryn-
geal edema prior to a tissue diagnosis of malignancy.
The relief of obstructive symptoms by radiation thera-
py may provide sufficient time to work up the cause of
SVCS, thus allowing for more specific treatment.
Radiotherapy for the treatment of a thoracic malignan-
cy or lymphoma may be appropriate, whereas radio-
therapy for the treatment of an underlying thrombosis
or granulomatosis causing the obstruction would be
inappropriate. Therefore, delaying treatment for 1 to
2 days if necessary to establish a firm tissue diagnosis is
appropriate.
Dosage.
Radiation treatment is initiated at high-
dose fractions daily for the first few days. This treat-
ment regimen is usually followed by conventional low
daily doses. The total dose is dependent on the
underlying tumor histology. Lymphomas are general-
ly treated with 3000 to 4000 cGy, whereas carcinomas
require 4000 to 5000 cGy or more to achieve control.
Lower doses of radiation treatment may be consid-
ered in cases in which systemic disease is present and
short-term palliation is the goal. Because of the limit-
ed tolerance of the heart and spinal cord to radiation,
short duration, high-dose programs are used. Physi-
cians must be aware of this dosage intensity in treat-
ing patients who are receiving chemotherapeutic
agents such as doxorubicin, which can enhance radia-
tion toxicity.
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