食管癌累及野照射淋巴结引流区受照剂量分析

Analysis of doses to lymph node drainage areas during involved-field irradiation for esophageal cancer

目的 分析食管癌三维适形累及野照射时相应淋巴结引流区受照剂量.方法 回顾分析2000-2004年间81例食管癌患者资料,依据病变部位分别勾画相应淋巴结引流区,分析各淋巴结引流区PTV的体积剂量学参数.结果 患者VPTV-n30、VP rv-n35、VPTV-n40、VPTV-n45、VPTV-n50中位数分别为73％、70％、67％、64％、58％.处方剂量大小与VPTV-n30、VPTV-n35无关（P=0.215、0.054）,与VPTV-n40～50有关（P =0.027、0.002、0.000）;照射野数多少与VPTV-n30～45无关（P=0.438、0.535、0.425、0.313）而与VPTV-n50有关（P=0.045）;病变食管钡餐造影X线长度及PTV大小与V PTV-n30～50均有关（所有P＜0.05）.单因素方差分析结果显示胸上段的VPTV-nx值均大于胸中段及胸下段,且VPTV-n30～35值的大小因病变部位不同差异有显著性（P=0.028、0.045）,而VPTV-n40～50则未见显著性差异（P=0.076、0.173、0.695）.VPTV-nx值大小对患者长期生存均无影响（所有P＞0.05）.结论 食管癌三维适形累及野照射时相应淋巴结引流区受到一定剂量照射,可能对预防区域淋巴结转移有一定作用,这有待临床研究进一步证实.

Objective To analyze the doses to lymph node drainage areas during involved-field irradiation （IFI） in three-dimensional conformal radiotherapy （3DCRT） for esophageal cancer （EC）.Methods A retrospective analysis was performed on the clinical data of 81 patients with medically inoperable thoracic EC who received IFI from 2000 to 2004.The lymph node drainage areas were delineated based on the lesions,and the dose-volume parameters of the planning target volume （PTV） of each lymph node drainage area was analyzed.Results The median values of V30,V35,V40,V45,and V50 were 73 %,70%,67%,64%,and 58%,respectively.The prescribed dose was not significantly correlated with V30 and V35 （P =0.215,0.054）,but significantly correlated with V40 and V50 （P =0.027,0.002,0.000） ; the number of radiation fields was not significantly correlated with V30 and V45 （P =0.438,0.535,0.425,0.313）,but significantly correlated with V50（P =0.045） ;the length of lesion on barium meal examination and volume of PTV were significantly correlated with V30 and V50 （all P 〈 0.05）.The one-way analysis of variance showed that the Vx value of upper-thoracic segment was greater than those of middle-and lowerthoracic segments （P =0.028,0.045） ; the values of V30 and V35 varied significantly between different lesions,but there were no significant differences in the values of V40 and V50 （P =0.076,0.173,0.695）.The Vx value had no significant impact on the long-term survival of patients （all P 〉 0.05）.Conclusions The lymph node drainage areas of EC receive a considerable dose with IFI in 3DCRT,which may play a certain role in preventing regional lymph node metastasis,but more clinical studies are needed.