Sensorineural hearing loss induced by radiation as a late effect: five cases followed by audiogram

Objective: we studied the progression of the late radiation-induced sensorineural hearing loss (SNHL) to discuss the pathological mechanism responsible for the progression with referring to past reports. Methods: five cases were selected among the SNHL cases diagnosed at the Department of Otolaryngology, Hokkaido University. All the cases were followed up with audiograms. Results: all of the five cases showed gradual progression of SNHL, which developed mostly 1–2 years after irradiation for brain tumors. Two of them showed rapid progression from time to time with sudden onset in their clinical courses. All the patients were resistant to any medication such as steroid, vitamin B12 or cerebral circulation activators. Conclusion: two patterns of progressions of radiation-induced hearing loss were observed. Both of them were considered to be explainable by ischemic changes of the vessels as reported earlier. Since there is no effective treatment for radiation-induced SNHL, it is most important to enlighten clinicians in general on this disease.