Side effect of head and neck radiotherapy: optic neuropathy

Abstract

Therapeutic irradiation of the head and neck region for control of tumor growth and for palliation of tumor mass effect, as well as stereotactic surgery increased in use in recent years, having a wide applicability. Despite technological advances, radiation-induced optic neuropathy is serious complication of this kind of treatment. Very important is early recognition of the disorder and treatment in incipient phases. Radiation damage could be acute (appearing during radiotherapy), early-delayed (occurring within 3 months after initial exposure) and late-delayed delayed radionecrosis, within 6 months to 10 years after exposure). Theories of vascular occlusion, demyelination, free radical injury, direct damage to cellular DNA, damage to the blood-brain barrier have been proposed to explain the pathophysiology. Patients commonly presents with unexplained, painless visual loss in one or both eyes, visual field defects, pupillary abnormalities and defective color vision. For both detection and management an important tool is Magnetic Resonance Imaging with and without contrast agents. Systemic corticosteroids, hyperbaric oxygen therapy free-radical scavengers showed some efficiency in treatment, especially in acute phases. A promise in treatment shows intravitreal triamcinolone acetonide injections and anti-VEGF molecules. But there is still no therapy that has been proven effective. The visual prognosis is poor, so we want to raise a alarm signal with this paper: awareness of this side-effect and mostly its prevention should be the way in managing patients who receive therapeutic irradiation for intracranial, sinus, nasopharyngeal, intraorbital and intraocular tumors.