Inner ear deficits in irradiated nasopharyngeal carcinoma survivors.

OBJECTIVES/HYPOTHESIS Despite the advancement of concurrent chemoradiotherapy, inner ear symptoms such as hearing loss, tinnitus, or vertigo/dizziness are still experienced in irradiated nasopharyngeal carcinoma (NPC) survivors. This study utilized an inner ear test battery to assess the causes and sequence of inner ear deficits in irradiated NPC survivors with a mean interval of 10 years after radiotherapy. STUDY DESIGN Retrospective study. METHODS Thirty-six irradiated NPC survivors were enrolled. Otoscopy and an inner ear test battery comprising audiometry were performed, as well as ocular vestibular-evoked myogenic potential (oVEMP), cervical VEMP (cVEMP), and caloric tests. RESULTS Otoscopic examination revealed middle ear complications in 37 ears (51%), including radiation-induced otitis media in 32 ears and otitis media with effusion in five ears. Percentages of abnormal cVEMP test, oVEMP test, bone-conducted mean hearing level, and caloric test were 91%, 75%, 67%, and 39%, respectively, exhibiting a significantly declining sequence in inner ear deficits. Most (67%) NPC survivors had inner ear deficit originated from peripheral vestibular lesion, mainly due to sequela of otitis media. In contrast, 33% of them had inner ear deficit caused by central vestibular disorder. CONCLUSIONS A significant sequential decline in inner ear function of irradiated NPC survivors was observed from the saccule to the utricle, cochlea, and semicircular canals. Most of them were due to sequela of otitis media, followed by central vestibular disorder. LEVEL OF EVIDENCE 4.