ABSTRACT

Objective:

Our purpose was to fi nd out effect of radiation therapy applied for nasopahyngeal carcinoma on the middle and inner ear functions.

Methods:

Sixty-six ears of 33 patients who were scheduled for radiation therapy for nasopharyngeal carcinoma were included in the study. The inclusion criteria were a normal otoscopic examination and tympanogram, a lack of conductive deafness on pure tone audiometry, and a lack of a history of previous otologic surgery or ototoxicity. Patients who had middle ear effusion in the follow up were excluded. Pure tone and speech audiometry, tympanometry and otoacoustic emission (OAE) testing were performed. Each patient was irradiated with a total dose of 7000 cGy. Co-60 (Theratron-780 Canada) was used in the radiotherapy, and a total of 7000 cGy was given.

Results:

In the 9-month follow up, 63.6% of the patients were excluded from the calculations due to the development of middle ear effusion. The PTAs of bone conduction were 16.1 dB and 20 dB before and 9 months after radiotherapy, respectively (p>0.05). The frequency specifi c pure tone results obtained before and 9 months after radiotherapy were not signifi cantly different (p>0.05). The results of TEOAE testing during the follow up were not signifi cantly different (p>0.05). There was no signifi cant change in the DPOAE results (p>0.05) except for in the 2 Hz frequency region, where a signifi cant amplitude reduction was observed in the 9th month compared to the initial recording (p=0.03)

Conclusion:

Cochlear damage can occur in the short term after radiation treatment for nasopharyngeal carcinoma. This damage, which occurs in the middle portion (2 kHz region) of the cochlea, is at subclinical level and does not lead to a hearing loss detectable by audiometry. The impact of radiation therapy on the inner ear may vary, depending on the application of different radiotherapy protocols in nasopharyngeal carcinoma.