Long-term sensorineural hearing deficit following radiotherapy in patients suffering from nasopharyngeal carcinoma: A prospective study

Abstract

Background. This was a prospective study to evaluate the effect of radical external irradiation on inner ear function after treatment of nasopharyngeal carcinoma. Methods. Pure tone audiograms were performed at regular intervals before, after, and up to 4.5 years following completion of radiotherapy. Results. Two hundred ninety-four patients (526 ears) were included. Within 3 months after radiotherapy, deterioration of bone conduction threshold at 4 kHz and pure tone average (average of 0.5 kHz, 1 kHz, and 2 kHz) were noted in 164 ears (31%) and 75 ears (14%), respectively. Patients older than 50 years and ears with threshold below 60 dB at 4 kHz before radiotherapy were significant factors (p < 0.01 and p < 0.001) associated with a 4 kHz loss. In 40% of these ears, recovery was evident at 2 years. With follow-up for 4.5 years, the probability of significant threshold deterioration increased with time. Conclusion. Sensorineural hearing loss started soon after radiotherapy. Early changes could be reversible while the probability of persistent hearing loss continued to increase.