Whole Brain Radiation Therapy Side Effects

The side effects of Radiation Therapy can be classified as Acute, Subacute
and Delayed.

Acute reactions occur during the course of treatment and are temporary.
They are manifested as signs of increased inter-cranal pressure or
worsening of neurological deficits. They results from an increase in cerebral
edema(abnormal accumulation of fluid). The administration of
corticosteroids usually decreases or alleviates symptoms. Steroids are
generally administered during the course of therapy to prevent this
occurrence. Other acute reactions are nausea, vomiting, anorexia(loss of
apetite), fatigue, alopecia(loss of hair) and skin irritation.

Subacute reactions generally develop one to three months after completion
of therapy. These are temporary in nature. Symptoms include anorexia(loss
of apetite), sleepiness, lethargy(drowsiness) and an increase in neurological
deficits. These effects result from the temporary disruption of myelin
formation, which helps speed the relay of nerve signals. It takes
approximately six weeks for myelin to repair.

Delayed reactions usally occur 6-24 months after completion of therapy.
These effects are irreversible and often progressive. They result from direct
injury to brain tissue and blood vessels. These reactions are due to changes
in the white matter and death of brain tissue caused by radiation-damaged
blood vessels. Symptoms vary from mild to severe decreased intellect,
memory impairment, confusion, personality changes and alteration of the
normal function of the area irradiated. Leukoencephalopathy(degeneration
of the white matter) occurs at the tumor site and surrounding irradiated brain.
The clinical manifestations range from mild cognitive neurological
impairment to dementia to death. Those at increased risk for long-term
radiation effects are children less than 2 and adults over 50 years of age.
Long-term effects can be initially managed to some degree with
corticosteroids and surgery to remove necrotic tissue.
Other long-term
reactions include loss of vision, development of secondary
malignancies(oncogenesis) and pituitary-hypothalamic dysfunction(changes
in normal hormone levels)leading to problems with your thyroid, sugar
metabolism, fertility or ability to process water.
//cancernet.nci.nih.gov/peb/radiation/index.html