鼻咽癌放疗后复发18FDG PET-CT定位再程适形放疗的疗效分析

目的探讨鼻咽癌放疗后复发采用18FDGPET—CT定位再程三维适形放疗的疗效、不良反应及失败原因。方法对56例鼻咽癌放疗后复发患者用信封法随机分为18FDGPET—CT定位三维适形放疗组（PET-CT组）和普通CT定位三维适形放疗组（普通CT组），每组各28例。PET—CT组采用PET-CT扫描定位，经PET—CT扫描后将扫描数据输入治疗计划系统，将PET图像和CT图像融合后进行靶区（大体肿瘤体积和计划靶体积）和重要脏器勾画、三维重建，制定治疗计划后常规分割三维适形放疗40Gy左右，然后适当缩野放疗至总剂量50～60Gy。普通CT组采用普通CT定位设野，三维适形放疗至相同剂量。两组放疗后均用TP方案（紫杉醇135～175mg／m2，dl；顺铂40mg，d2—4）辅助化疗4～6周期。结果PET—CT组大体肿瘤体积和计划靶体积均小于普通CT组，两者差异有统计学意义（均尸〈0．05）。PET—CT组再次局部复发17例，中位复发时间11．7个月，普通CT组再次局部复发19例，中位复发时间10．3个月，两者差异有统计学意义（P〈0．01）。多因素分析表明，在年龄、性别、卡氏评分、T分期和疗前大体肿瘤体积等因素中，只有T分期和疗前大体肿瘤体积是独立的预后因子，T分期早和疗前大体肿瘤体积≤100cm3者预后好，P值均〈0．01。结论鼻咽癌放疗后复发用PET—CT定位三维适形再程放疗可以优化放疗计划，延长中位复发时间，分期早的病变预后好。

Result of 18FDG PET-CT positioning three-dimensional conformal radiotherapy for Nasopharyngeal carcinoma recurrence after radiotherapy

Objective To analyse the result of 18FDG PET-CT positioning three-dimensional conformal radiotherapy(3DCRT) for Nasopharyngeal carcinoma recurrence after radiotherapy.Methods56 cases of Nasopharyngeal carcinoma recurrence after radiotherapy patients were randomly divided into 18FDG PET-CT group and the normal CT group.The location of PET-CT group’s cases was determined by PET-CT and the date was transmitted to the treatment planning system(TPS),the PET image and CT image were fused together;The target volume and critical organs were determined by the fused image,then conventional fraction’s 3DCRT(40Gy or so) was followed to a total dose of radiotherapy 50-670Gy by reduced radiation field;The location of normal CT group’s cases was determined by normal CT and were treated by 3DCRT to the same dose.All cases were treated by the TP program(paclitaxel 135-175mg/m~2,d1,cisplatin 40mg,d2-d4) adjuvant chemotherapy for 4-6 cycles later.Results The average GTV’s and PTV’s volume of the PET-CT group were smaller than that of the normal CT group,there was statistically significant difference(all P <0.05) between the two groups;The median recurrence time of the PET-CT group was 11.7 months,and the median recurrence time of the normal CT group was 10.3 months,there was significant difference between the two groups(P <0.01);Multivariate analysis showed that early T stage lesions and small GTV(≤100cm~3) were better than that of others(all P <0.01).Conclusions PET-CT positioning 3DCRT can optimize the radiation treatment planning and extend the median time to recurrence for Nasopharyngeal carcinoma recurrence after radiotherapy,the patients with early stage lesions have better prognosis than others.