Dosimetric parameters associated with conductive or sensorineural hearing loss 5 years after intensity-modulated radiation therapy in nasopharyngeal carcinoma

Abstract

Background: Most previous studies are separate dosimetric analyses of conductive or sensorineural hearing loss, and they are not conducive to a comprehensive assessment of auditory radiation damage.

Aims/objectives: Our study aimed to evaluate the long-term incidence of sensorineural hearing loss (SNHL) or conductive hearing loss (CHL) in patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiation therapy (IMRT), and to investigate the relationship between SNHL or CHL and patient factors, treatment-related factors, and radiation dose parameters.

Material and methods: Seventy patients (117 ears) with NPC, who were also treated with IMRT in our hospital from 2006 to 2014, were retrospectively analyzed. Radiation doses to the Eustachian tube (ET), middle ear (ME), cochlear (Co), and internal auditory canal (IAC) were assessed. Pure tone audiometry and impedance audiometry were performed before and during the follow-up period. The relationships between low-frequencies (0.5–2 kHz) or high-frequency (4 kHz) SNHL/CHL and radiotherapy dose parameters were analyzed.

Results: Of the 117 ears studied, 7.69% had low-frequency SNHL, 35.9% had high-frequency SNHL, 23.93% had low-frequency CHL, and 18.80% had high-frequency CHL. The incidence of high-frequency CHL was higher in the T4 group than in the T (1–3) group (p < .05). When IAC D_max > 42.13 Gy or IAC D_mean > 32.71 Gy, the risk of high-frequency SNHL increased in NPC patients. When ME D_max > 44.27 Gy, ME D_mean > 29.28 Gy, or ET D_max > 57.23 Gy, the risk of high-frequency CHL in NPC patients increased.

Conclusions and significance: SNHL and CHL remain common ear complications after IMRT for NPC. IAC D_max, IAC D_mean, ME D_max, ME D_mean, and ET D_max all need to be carefully considered during the IMRT treatment protocol.

Chinese abstract

背景：以往的研究大多是针对传导性或感音神经性听力损失的单独剂量分析, 无助于全面评估听觉辐射损伤。

目的：本研究旨在评估调强放疗（IMRT）后鼻咽癌（NPC）患者感音神经性听力损失（SNHL）或传导性听力损失（CHL）的长期发生率, 并探讨SNHL或CHL与患者因素、治疗相关因素和辐射剂量参数的关系。。

材料与方法：回顾性分析2006-2014年我院收治的70例（117耳）鼻咽癌患者的临床资料。评估耳咽管（ET）、中耳（ME）、耳蜗（CO）和内耳道（IAC）的辐射剂量。随访前后分别进行纯音测听和阻抗测听。分析了低频（0.5～2 kHz）和高频（4 kHz）SNHL/CHL与放射治疗剂量参数的关系。

结果：117只耳中, 7.69%的耳有低频SNHL, 35.9%的耳有高频SNHL, 23.93%的耳有低频CHL, 18.80%的耳有高频CHL。T4组高频CHL的发生率高于T（1-3）组（P<.05）。当IAC D_max >42.13 Gy或IAC D_mean >32.71 Gy时, 鼻咽癌患者的高频SNHL风险增加。当ME D_max >44.27 Gy、ME D_mean >29.28 Gy, 或ET D_max >57.23 Gy时, 鼻咽癌患者发生高频CHL的风险增加。

结论与意义：鼻咽癌IMRT术后SNHL和CHL仍为常见的耳并发症。在IMRT治疗方案中, IAC D_max 、IAC D_mean 、ME D_max 、ME D_mean 和ET D_max 都需要仔细考虑。

Keywords:

• Nasopharyngeal carcinoma
• intensity-modulated radiation therapy
• sensorineural hearing loss
• conductive hearing loss

Acknowledgments

The authors thank The International Atomic Energy Agency Program (Grant No. E33039) and the Shanghai Health and Family Planning Commission Program (Grant No. 201640062), China

Disclosure statement

No potential conflict of interest was reported by the authors.