A PROSPECTIVE LONGITUDINAL-STUDY ON RADIATION-INDUCED HEARING-LOSS

Recent clinical reports indicate that patients receiving radiotherapy that includes the auditory system iu the treatment volume are likely t o develop an irradiation-induced healing loss. Although the early, pre sumed reversible, conductive hearing impairment due to secretory otiti s media following radiotherapy is a sequela well known by radiation on cologists, permanent hearing loss, both conductive and sensorineural, is believed to be rare. A prospective study was performed enrolling pa tients receiving postoperative radiotherapy for unilateral parotid tum ors. Audiometric results prior to irradiation were compared with those obtained 2 rears later. Up to 50% of the patients (9 of 18) developed a clinically relevant hearing loss in the irradiated ear, both conduc tive and/or sensorineural. The contralateral ear remained unaltered. T he hearing loss was permanent in 6 patients (33%) and affected their q uality of life. The data suggest that changes occur in the inner ear a s well as in the auditory nerve and auditory brain stem with conventio nal irradiation schemes with daily fractions of 2 to 2.5 Gy with a tot al dose of 50 Gy.