术前放疗中食管胃结合部病灶移动度分析

目的 探索食管胃结合部(GEJ)腺癌在术前放疗过程中移动度范围。方法 纳入接受GEJ腺癌术前同步放化疗14例患者,胃镜直视下于肿瘤上、下缘或四周分别置入钛夹标记肿瘤边缘。8例患者采用4DCT定位共获得位于GEJ的8个钛夹分次内图像98套供分析,12例患者在放疗前5次、第7、12、17、22次分别进行CBCT共获得分次间图像90套供分析。配对t检验差异。结果 肿瘤分次内动度在左右、腹背、头脚方向上分别为(0.92±0.95)、(2.27±2.73)、(9.95±5.48) mm,分次内动度头脚方向大于左右方向(P=0.000)和腹背方向(P=0.000),腹背方向大于左右方向(P=0.000)。肿瘤分次间动度在左右、腹背、头脚方向上分别为(6.56±4.19)、(5.69±3.29)、(6.49±4.37) mm,分次间动度左右方向和头脚方向均大于腹背方向(P=0.031、0.044),左右方向和头脚方向差异不显著(P=0.956)。为保证90%肿瘤体积接收95%处方剂量,在GEJ病灶的左右、腹背、头脚方向分别外放19.4、14.6、27.2 mm,可在术前放疗期间较好覆盖肿瘤分次内和分次间的移动度。结论 GEJ肿瘤在术前放疗中分次内和分次间移动度均较大,需在精确治疗中给予考虑并寻找新方法限制肿瘤移动。

Motion of gastroesophageal junction adenocarcinoma during preoperative radiotherapy

Objective To evaluate the range of motion of gastroesophageal junction (GEJ) adenocarcinoma during preoperative radiotherapy.Methods Fourteen consecutive patients who received preoperative chemoradiotherapy for GEJ adenocarcinoma were included in this study.Fiducial markers were placed on the upper and lower edges of and around the primary tumor under a gastroscope.Eight patients underwent four-dimensional computed tomography to obtain 98 intrafractional images containing 8 fiducial markers at the GEJ.Twelve patients underwent cone-beam computed tomography at the 1 st to 5th,7th,12th,17th,and 22nd courses of radiotherapy to obtain 90 interfractional images.The paired t test was used for difference analysis.Results The intrafractional tumor displacements in left-right (LR),ventro-dorsal (VD),and cranio-caudal (CC) directions were 0.92±0.95 mm,2.27±2.73 mm,and 9.95±5.48 mm,respectively;the motion in CC direction was larger than that in LR or VD direction (P=0.000 or P=0.000);the motion in VD direction was larger than that in LR direction (P=0.000).The interfractional tumor displacements in LR,VD,and CC were 6.56±4.19 mm,5.69±3.29 mm,and 6.49±4.37 mm,respectively;the motion in LR or CC direction was larger than that in VD direction (P=0.031 or P=0.044);there was no significant difference between the motions in LR and CC directions (P=0.956).In order to ensure 95% of prescribed dose to at least 90% of the tumor volume,the margins from GEJ lesion in LR,VD,and CC directions were 19.4 mm,14.6 mm,and 27.2 mm,respectively,which could cover both intrafractional and interfractional tumor displacements during preoperative radiotherapy.Conclusions GEJ tumor has a wide range of movement in preoperative intra-and inter-fractional radiotherapy.This should be considered for precise radiotherapy,and a new method should be selected to limit tumor movement.