| Objective:The purpose of this paper is to observe the hearing changes of patients with nasopharyngeal carcinoma before and after treatment,to evaluate the exposure doses to the middle ear and inner ear,to explore the relevant factors and risk factors affecting hearing function,and to provide theoretical basis for the protection of hearing function.Methods:From February 2017 to August 2017,32 patients with nasopharyngeal carcinoma(NPC)were collected from the radio-therapy Department of The First Affiliated Hospital of Guangxi Medical University.All patients were treated with radical intensity modulated radiotherapy.The audiological information was collected before radiotherapy,at the end of radiotherapy and 3 months after radiotherapy.By analyzing the recent changes of audiology and evaluating the radiation doses of different structures of the middle ear and inner ear,we explored the related factors and risks that might affect hearing.Results:By the end of 3 months after radiotherapy,32 patients(64 ears)entered the study.Conduction hearing loss(CHL),sensorineural hearing loss(SNHLL)and mixed hearing loss(MHL)existed before treatment.The results of pure tone audiometry showed that the air conduction and bone conduction hearing decreased in different degrees before and after treament,and the low frequenc ies(250Hz to 4000Hz)hearing of air conduction showed a tendency of improvement firstly and then deteriorated,while the high frequency hearing(8000Hz)deteriorated gradually with time,and the hearing loss of 8000 Hz was the most obvious.The hearing of all frequencies of bone conduction(250Hz to 4000Hz)showed a tendency of deterioration with time,and the hearing losses of 250 Hz and 4000 Hz were the most obvious.The results of acoustic impedance showed that there were no significant changes in the five indexes(Sound alignment,width,peak pressure of tympanic chamber,eustachian tube function,tympanogram).Dose assessment of the ear structures showed that the average dose of cochlea,vestibule,inner auditory canal,tympanic cavity and osseous eustachian tube were respectively 4739.1 ±952.8 c Gy,3733.7 ±719.8c Gy,4440.5 ±898.4c Gy 4257.3 ±730.9c Gy 5922.2 ±747.9c Gy.Among them,there were s ignificant differences in the average irradiation dose of the coc hlea,vestibular,internal auditory,osseous eustachian tube,and the average dose of the tympanic cavity was not statistically significant.The possible influencing factors of high frequency SNHL in 3 months after radiotherapy were analyzed.Univariate analys is showed that there were statistical significances in sex(P< 0.001)and cumulative dose of cisplatin(P<0.013).Multivariate analys is showed that there was significant difference in sex(OR=0.043).Conclusions: 1.CHL,SNHLL and MHL existed commonly before treatment,and there were hearing impairment in both air conduction and bone conduction after treatment,especially in high frequenc ies hearing.2.The middle ear and inner ear were still exposed to higher dose,and reasonable limited doses of ear still needs further study.3.The occurence of high frequency SNHL after treatment of nasopharyn-geal carcinoma is correlated with sex,and the female is the protective factor of high frequency SNHL. |
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