Hearing
Radiation Therapy (RT) Toxicity
Children who have primary tumors of the head and neck area or brain frequently need radiation therapy (RT) as part of their curative therapy.
RT given to the external, internal and middle ear can cause damage to these structures1
Side effects can occur both during treatment (early) and months to years following therapy (late)3
Early Effects:
- Desquamation of the columnar epithelium lining the ears and covering the ossicles
- Edema of the mucosa within the ear3
- Otitis media: inflammation and fluid accumulation in middle ear
Late Effects:
Hearing loss secondary to RT is usually permanent and can be sensorineural or conductive depending on the structures affect by the RT3
External Ear:
- Altered production of cerumen along with epithelial desquamation leading to plugging of the ear canals which persists after the completion of therapy3
- Direct effects of RT on cartilaginous structures may lead to stenosis or necrosis of the ear canal and chronic RT induced otitis and hearing loss3
- Chrondronecrosis can also occur in the cartilage of the external ear3
Middle Ear:
- Scarring and damage to ossicles as a result of RT
Inner Ear:
- Cranial RT when used alone typically results in ototoxicity only when cochlear dosage exceeds 30 Gy4
- Sensorineural hearing loss can occur as a result of the radiation affecting the connection between the auditory cortex and cochlea3
RT induced hearing loss usually occurs many years after treatment if it is the only modality given as treatment3
Combination RT and chemotherapy can result in hearing loss within the first few years after therapy3
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Key Factors |
Contributory Factors |
Radiation Therapy (RT) Risk Factors |
Dose of 30 Gy or more4
RT given concurrently or sequentially with other ototoxic drugs:
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Younger age at treatment4
Higher radiation dose4
Chronic otitis or cerumen impaction before treatment4
CNS tumor4
CSF shunting4 |
