不同照射方式下非常规分割方案的生物效应对鼻咽癌疗效的影响

The Effect of Biological Effect of Unconventional Fractionation Radiotherapy Schema in Different Radiation Modality on Efficacy of Nasopharyngeal Cancer

[目的]探讨不同照射方式(调强和普放)中采用非标准分割方案的疗程总剂量及分次剂量、总时间及分次数对鼻咽癌疗效的影响。[方法]回顾性分析2004年1～12月经病理确认并进行放射治疗且随访到2009年12月的资料完整的Ⅱ～Ⅳ期鼻咽癌病例162例,调强组57例,普放组105例;调强组和普放组给予肿瘤的总平均物理剂量分别为72Gy和76Gy,所对应的生物等效剂量(EQD2T)分别是75.5Gy和70Gy。调强组采用鼻咽加上下颈淋巴引流区同期加速推量动态调强放疗技术,普放组采用面颈联合野加颈部切线野常规放疗技术。[结果]调强组和普放组5年生存率分别为71.9%和70.5%,5年局控率分别为84.2%和78.1%,5年无瘤生存率分别为73.7%和71.4%,均无显著性差异。5年并发症发生率调强组低于普放组(65.9%vs85.1%,P=0.016)。[结论]调强和普放照射方式中采用72～76Gy物理剂量所反映的生物效应对鼻咽癌疗效影响不明显,两组的生存率和局控率接近。调强技术降低放疗损伤与晚反应组织生物剂量无关,但和物理优化技术有关。

[Purpose] To explore the influence of the total dose,fractionated dose,total time and total fractions of the unconventional fractionated radiotherapy with different delivery techniques on the therapeutic efficacy of nasopharyngeal cancer（NPC）.[Methods] From Jan.to Dec.2004,the clinical data of 162 pathologically confirmed,Ⅱ~Ⅳ stage,follow-up to Dec.2009 and received radiotherapy NPC patients were analyzed retrospectively.They were divided into IMRT group（n=57） and conventional RT group（CRT）（n=105）.The total average physical dose in IMRT and CRT group was 72Gy and 76Gy,the total biological equivalent dose（EQD2T） was 75.5Gy and 70.0Gy respectively.IMRT group received simultaneous modulated accelerated radiation therapy in nasopharyngeal and lymphatic drainage areas of the neck;CRT group received conventional radiotherapy in face,neck joint field plus neck wild tangent.[Results] The 5 year survival rate and 5 year local regional control rate were 71.9% and 84.2% respectively in IMRT group,compared to 70.5% and 78.1% respectively in CRT group,with no significant difference.The 5 year complication rate in IMRT group and CRT group was 65.9% and 85.1%,with significant difference（P=0.016）.[Conclusion] A biological dose equivalent to a physical dose of 72-76Gy was no significant influence on the treatment effectiveness of NPC whether IMRT or CRT is applied.The survival rate and local control rate in the two groups is similar.The relatively mild radiation injury by IMRT is due to the physical optimization technique and is not related to the biological dose of the late response tissue.