Radiation-induced hearing impairment in patients treated for malignant parotid tumor.
Radiation-induced hearing loss was evaluated in 21 patients with unilateral malignant parotid tumors treated with surgery and radiotherapy. The contralateral ear was used as a control. Eight patients (38%) were found to have a reduction in static compliance of the tympanic membrane (type B tympanogram) in the irradiated ear. By audiometry, significant hearing loss was found in 9 patients (43%). These hearing losses were mainly sensorineural, as shown by a similar reduction in both air and bone conduction, although mixed-type hearing loss existed in some patients. A statistically significant difference in incidence of 67% versus 0% (p = .0085) was noted for patients with a cochlear dose of greater than or equal to 60 Gy, in comparison to those receiving doses of less than 60 Gy. A type B tympanogram was also found to be a prognostic factor for significant sensorineural hearing loss. Patients with type B tympanograms had a much higher incidence of significant sensorineural hearing loss than those with type A tympanograms (88% versus 15%, p = .02). This study clearly shows that radiotherapy can induce significant hearing impairment, especially when the cochlear doses are higher than 60 Gy.
Chen
W C
WC
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Liao
C T
CT
Tsai
H C
HC
Yeh
J Y
JY
Wang
C C
CC
Tang
S G
SG
Hong
J H
JH
D000158:Acoustic Impedance Tests / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone / Q000379:methods; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010307:Parotid Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000150:complications*; D011878:Radiotherapy / Q000009:adverse effects*; D012189:Retrospective Studies; D012720:Severity of Illness Index