Prospective study of sensorineural hearing loss following radiotherapy for nasopharyngeal carcinoma

Objectives: To investigate the severity and incidence of sensorineural hearing loss in patients with nasopharyngeal carcinoma treated with radiotherapy. Methods: Forty-two patients with nasopharyngeal carcinoma were treated with conventional radiotherapy. Audiological testing was performed to compare patients' hearing before and at varying stages after radiotherapy. Results: At one month post-radiation, a significant hearing threshold increase was seen only for high frequencies. At 12, 24 and 60 months post-radiation, significant threshold increases were observed at speech frequencies (4.0 and 8.0 kHz), compared with pre-radiation data. The mean values of wave I, III and V latencies and of the I-V interpeak latency intervals were not significantly altered at one month post-radiation, but were significantly prolonged at 12, 24 and 60 months post-radiation, compared with pre-radiation data. Conclusion: In patients with nasopharyngeal carcinoma treated with radiotherapy, the severity and incidence of radiation-induced sensorineural hearing loss increased with time, especially at high frequencies. This hearing impairment may be due to changes in the cochlea and/or the retrocochlear auditory pathway.