早中期鼻咽癌放疗晚期损伤的临床分析

Clinical analysis of radiation induced late injury in patients with prometaphase nasopharyngeal carcinoma

目的:回顾性分析早中期鼻咽癌长期生存者正常组织晚期损伤的相关因素,探讨常规放疗条件下减少晚期损伤的方法。方法:收集在门诊复查的2000-03-06-2002-12-20本院收治的Ⅰ～Ⅱ期初治鼻咽癌患者183例,为非连续病例。全组病例均用6MVX射线行外照射。鼻咽部设野采用面颈联合野照射103例,耳前野照射80例,颈部采用切线野照射。鼻咽部照射剂量≤70Gy150例,>70Gy33例,中位剂量70Gy(64～82Gy)。颈部照射剂量≤50Gy45例,>50Gy138例,中位剂量68Gy(49～85Gy)。结果:当鼻咽部照射剂量≤70Gy或>70Gy时,晚期损伤分别为口干91.3%(137/150)、100.0%(33/33),张口困难48.0%(72/150)、81.8%(27/33),放射性颞叶损伤14.7%(22/150)、36.4%(12/33),后组颅神经损伤17.3%(26/150)、42.4%(14/33)。当颈部剂量≤50Gy或>50Gy时,晚期损伤分别为:颈纤维化22.2%(10/45)、63.8%(88/138),后组颅神经损伤11.1%(5/45)、25.4%(35/138)。照射剂量与晚期损伤呈明显正相关。结论:二野照射方法剂量分布不合理,是造成早中期鼻咽癌正常组织迟发反应的主要原因。采用后装腔内放疗、鼻前野或鼻前面颈联合野等的方法有望减少危及器官的损伤。

OBJECTIVE：To retrospectively analyze the involved factor of radiation induced normal tissue late injury in long term survival patients with early stage nasopharyngeal carcinoma,and approach the improvement of conventional radiation technique to decrease the late complication.METHODS：The clinical data of 183 patients with stage Ⅰ/Ⅱ nasopharyngeal carcinoma undergone 6 MV-X ray radiotherapy from 03-06-2000 to 12-20-2002 were analyzed.Totally 103 patients were treated with facio-cervical portal and the other 80 patients were treated with pre-auricular portal.They all used tangential portal for neck irriadiation.The radiation doses of nasopharynx were ≤70 Gy delivered in 150 patients,while 70 Gy in 33 patients,and the medium dose was 70 Gy（64-82 Gy）.The cervical lymphatic doses were ≤50 Gy delivered in 45 cases and 50 Gy in 138 cases,and the medium dose was 68 Gy（49-85 Gy）.RESULTS：When the nasopharyngeal doses were prescribed≤70 Gy and 70 Gy,the frequencies of radiation induced late effects were showed below：xerostomia 91.3%（137/150） vs 100.0%（33/33）;Trismus 48.0%（72/150） vs 81.8%（27/33）.Radiation encephalopathy 14.7%（22/150） vs 36.4%（12/33）;lower cranial neuropathy 17.3%（26/150） vs 42.4%（14/33）.While the cervical doses were prescribed ≤50 Gy vs 50 Gy,the frequencies of late effeces were showed below：cervical subcutaneous fibrosis 22.2%（10/45） vs 63.8%（88/138）;Lower cranial neuropathy 11.1%（5/45） vs 25.4%（35/138）.The radiation dose was significantly positively correlated with the late effect rates.CONCLUSIONS：The dose distribution of two-portal radiation is unreasonable.It is the major cause of severe normal tissue late effects after radiotherapy in early stage nasopharyngeal carcinoma.The application of afterloading brachytherapy,anterior portal and anterior facio-cervical three-portal radiation technique may helpfully reduce the injury incidence of organs-at-risk.