Department of Radiation Oncology, Eye, Ear, Nose and Throat Hospital of Fudan University, Shanghai, China.
Radiother Oncol. 2009 Dec;93(3):530-3. doi: 10.1016/j.radonc.2009.09.013. Epub 2009 Oct 21.
This study evaluates the difference in damage to middle ear function with CRT and IMRT techniques in the treatment of nasopharyngeal carcinoma (NPC). We explore the isthmus of the Eustachian tube (ET) as the key anatomic site for the prevention of radiation-induced otitis media with effusion.
Eighty-two patients with NPC were divided into two groups: 40 patients treated with CRT and 42 patients treated with IMRT. The difference between dosage over the middle ear cavity and the isthmus of the ET was evaluated in both CRT group and IMRT group. All patients underwent hearing tests including pure tone audiometry and impedance audiometry before and after RT.
The dosage difference to the middle ear cavity and isthmus between these two groups was statistically significant (p<0.05). The difference in hearing test results between these two groups was also statistically significant (p<0.05). If we limited the dose to the middle ear cavity under 34 Gy and the dose to the isthmus under 53 Gy with IMRT, we may decrease radiation-induced OME even with the larger 2.25 Gy fraction size.
IMRT may have better protected the middle ear function compared with the CRT technique, even with larger fraction sizes than for the conventional CRT technique.
本研究评估了 CRT 和 IMRT 技术在治疗鼻咽癌（NPC）中对中耳功能损伤的差异。我们探讨了咽鼓管峡作为预防放射性分泌性中耳炎的关键解剖部位。
82 例 NPC 患者分为两组：40 例 CRT 治疗组和 42 例 IMRT 治疗组。评估了 CRT 组和 IMRT 组中耳腔和咽鼓管峡剂量差异。所有患者在 RT 前后均进行了听力测试，包括纯音测听和阻抗测听。
两组之间中耳腔和咽鼓管峡剂量差异具有统计学意义（p<0.05）。两组间听力测试结果差异也具有统计学意义（p<0.05）。如果我们限制 IMRT 治疗的中耳腔剂量低于 34Gy，咽鼓管峡剂量低于 53Gy，即使使用较大的 2.25Gy 分次剂量，也可能减少放射性分泌性中耳炎。
与 CRT 技术相比，IMRT 可能更好地保护了中耳功能，即使分次剂量大于常规 CRT 技术。
