Hearing Assessment after Treatment of Nasopharyngeal Carcinoma with CRT and IMRT Techniques.
OBJECTIVE
This study analyzed the long-term hearing loss after treatment of primary nasopharyngeal carcinoma to elucidate its causal factors.


METHODS
Ninety-two nasopharyngeal carcinoma patients were treated with radiotherapy or chemoradiotherapy. Pure tone audiometry was performed before the therapy and annually up to 9 years after completing treatment. The hearing thresholds were corrected for age-related deterioration and compared to the results without adjusting for age.


RESULTS
The mean air and bone conduction threshold with and without correction for age-related deterioration differed significantly 2-9 years after completing radiotherapy (p < 0.05). The audiometry results with age correction showed a flattened configuration compared to the results without age correction. The total radiation dose and radiation modality showed a causal relationship with a greater incidence of hearing loss after therapy (p < 0.05). There was more deterioration in the air and bone hearing thresholds with conformal radiotherapy than intensity-modulated radiotherapy (p < 0.001). A radiation dose >72 cGy resulted in more severe hearing loss than <72 cGy (p < 0.05).


CONCLUSIONS
Hearing loss after completing therapy should be corrected for age-related hearing deterioration to reveal the true extent to which the loss is a therapeutic complication. Both the radiation modality used and the dose were significantly associated with hearing loss.
Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan.
Chung-Feng
CF
Hwang
Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan.
Fu-Min
FM
Fang
Department of Otolaryngology, Chang Gung Memorial Hospital and Xiamen Medical Center, Fujian 361000, China.
Ming-Ying
MY
Zhuo
Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan.
Chao-Hui
CH
Yang
Graduate Institute of Audiology and Speech Therapy, National Kaohsiung Normal University, Kaohsiung 80201, Taiwan.
Li-Na
LN
Yang
Department of Otolaryngology, Chang Gung Memorial Hospital and Xiamen Medical Center, Fujian 361000, China.
Hui-Shan
HS
Hsieh
D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone / Q000379:methods; D001844:Bone Conduction / Q000187:drug effects; D002277:Carcinoma; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D034381:Hearing Loss / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D055815:Young Adult