Adverse radiation effect in the brain during cancer radiotherapy

Adverse radiation effect (ARE) in the brain is the reactive inflammation, vasculitis, and necrosis that occurs as a complication of radiotherapy. There are two main categories of ARE that result in vasogenic cerebral edema: first, a residual irritant mass of the targeted lesion; and second, radiation-damaged perilesional normal brain tissue in a reactive state. Radiation injury leads to fibrinoid and coagulative necrosis of different cell types and fibrinoid necrosis and hyalinization of vessels. The clinical consequence of ARE is neurologic impairment secondary to vasogenic edema in the normal brain. Neuroimaging may aid in differentiating tumor recurrence from ARE. However, imaging studies are not definitive, and their utility in this setting remains controversial. The management of patients with ARE is dictated by symptom occurrence. The definitive management of symptomatic ARE is craniotomy and resection. Alternative therapies include bevacizumab, laser-interstitial thermal therapy, and reirradiation.