鼻咽癌调强放射治疗口咽保护的初步研究

摘要

目的：研究鼻咽癌（ nasopharyngeal carcinoma，NPC）适形调强放疗（ intensity-modulated radiotherapy， IMRT）患者口咽危及器官勾画方法、口咽黏膜毒副反应防治与受照剂量-体积的关系。方法：2010年3月-2012年11月，在中山大学肿瘤防治中心连续收治的89例初治NPC患者进入研究，患者均接受适形调强放疗。口咽及下咽勾画为危及器官。放疗前及放疗中每周观察并评价咽喉部黏膜反应程度，定期随访患者口咽、下咽黏膜恢复情况，并结合口咽、下咽剂量体积直方图（ dose-volume histogram，DVH）进行分析。结果：口咽受照射的平均剂量为（4743.1±574.1）cGy（3469.5-6121.7cGy），下咽的平均剂量（4284.3±491.8）cGy （2867.6-6452.3cGy），0-4级急性口咽黏膜反应的发生率分别为15.7%、74.3%、8.9%、1.1%、0%。放疗过程中口咽黏膜反应与口咽受照平均剂量、V40、V45、V50呈正相关（P<0.01）。ROC曲线得出口咽受照射平均剂量诊断显著，放射性口咽黏膜炎的最佳临界点为4890.2cGy，曲线下面积为0.869（P<0.01）。结论：患者放射性口咽黏膜炎与口咽受照体积、剂量显著相关，建议口咽平均剂量小于4890cGy，下咽小于40-45Gy，同时应尽量减少50Gy以上剂量照射的体积。正确勾画口咽、下咽范围，综合口咽受照平均剂量和剂量体积，优化决定鼻咽癌调强放疗计划，对减少放射性口咽、下咽黏膜炎、提高患者生存质量具有重要意义。%Objective:To study the relationship between dose volume and acute mucosa reaction of oropharynx of nasopharyngeal carcinoma( NPC)with intensity modulated radiation therapy( IMRT). Methods:All 89 patients with newly diagnosed NPC were into the study diagnosed by pathology and underwent IMRT. Oropharynx and hypopharynx sketch were for organ at risk( OAR). Observe and evaluate the acute mucosa reaction before and after radiotherapy. Results:The average mean dose of oropharynx and hypopharynx was(4743. 1 ± 574. 1)cGy(3469. 5-6121. 7cGy) and(4284. 3 ± 491. 8)cGy(2867. 6-6452. 3cGy),respectively. 0-4 acute oropharynx mucosa reaction rates were 15. 7%,74. 3%,8. 9 %,1. 1%,0%. Oropharynx mucosa reaction during radiotherapy and mean dose,V40 ,V45 ,V50 , V54 were positively correlated(P<0. 01). ROC curve demonstrated that 4890. 2cGy was the best diagnosis critical point of the average dose to oropharynx for acute oropharynx mucositis[ the area under the curve was 0. 869(P<0. 01)]. Conclusion:The patients with radiation-induced oropharyngeal mucositis and oropharyngeal dose volume was significantly related,we suggest that the average dose to oropharyngeal and hypopharyngeal should be limit to 4890cGy and 40-45Gy,and try to reduce the irradiated volume of more than 50Gy. To correct sketch oropharyngeal and hypopharyngeal range,comprehensive oropharyngeal mean dose and dose volume is optimal decision of nasopha-ryngeal carcinoma with IMRT. To reduce the radioactive oropharyngeal and hypopharynx mucositis,improve the quality of life of patients is significant.