18FDG PET/CT定位三维适形放疗联合化疗对复发性直肠癌的疗效和预后分析

目的对比研究术后复发性直肠癌经18FDG PET/CT定位适形放疗联合化疗的疗效、副反应及失败原因。方法对64例术后局部复发性直肠癌患者随机分为18FDG PET/CT定位适形放疗组（PET/CT组）和普通CT定位适形放疗组（普通CT组）。PET/CT组用PET/CT扫描定位,将扫描数据输入三维治疗计划系统,将PET图像和CT图像融合后进行靶区（GTV与PTV）和重要脏器勾画、三维重建,制定计划后常规分割适形放疗40Gy左右,然后缩野放疗至总剂量60Gy～66Gy;普通CT组用普通CT定位设野,三维适形放疗至相同剂量;全组均辅助化疗4～6周期。结果放疗后全组CEA值平均为11.9ng/ml,较放疗前的16.4ng/ml显著下降,放疗前后差异有显著性统计学意义（P〈0.01）;PET/CT组的中位复发时间10.2个月,普通CT组的中位复发时间9.0个月,两者差异有显著性统计学意义（P〈0.01）;疗前GTV≤80cm3者预后好,是独立的预后因子（P〈0.01）。结论 PET/CT定位三维适形放疗术后复发性直肠癌可以优化放疗计划,联合化疗可以延长中位复发时间,分期早的病变预后好。

Analysis of 18FDG PET/CT positioning three-dimensional conformal radiotherapy and concurrent chemotherapy for local recurrence in postoperative rectal carcinoma

Objective To analyze the result of 18FDG PET/CT positioning three-dimensional conformal radiotherapy（3DCRT） and concurrent chemotherapy for local recurrence in postoperative rectal carcinoma.Methods 64 cases of local recurrence in postoperative rectal carcinoma patients were randomly divided into 18FDG PET/CT positioning 3DCRT group（PET/CT group）and the general CT positioning 3DCRT group（normal CT group）.The location of PET/CT group 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 and the treatment plan was worked out from the fused image,then conventional fraction＇s 3DCRT（40Gy or so） was followed to a total dose of radiotherapy 60Gy～66Gy by reduced radiation field.The location of normal CT group was determined by normal CT and treated by 3DCRT to the same dose.All patients were treated by concurrent chemotherapy to totally 4～6 cycles.Results After radiotherapy,the average CEA of the whole group was 11.9ng/ml.Before radiotherapy,the average CEA of the whole group was 16.4ng/ml.There was significant difference between the average CEA before and after radiotherapy（t=6.52,P0.001）.The median recurrence time of the PET/CT group was 10.2 months,and the median recurrence time of the normal CT group was 9.0 months.There was significant difference between the two groups（t=5.50,P0.001）.Multivariate analysis showed that small GTV（≤80cm3） were better than that of others（all P0.01）.Conclusion PET/CT positioning 3DCRT can optimize the radiation treatment planning for local recurrence in postoperative rectal carcinoma.The combined with concurrent chemotherapy can extend the time to recurrence.