食管癌累及野照射淋巴结引流区受照剂量分析

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V_PTV-n30、V_PTV-n35、V_PTV-n40、V_PTV-n45、V_PTV-n50中位数分别为73%、70%、67%、64%、58%。处方剂量大小与V_PTV-n30、V_PTV-n35无关(P=0.215、0.054),与V_PTV-n40~50有关(P=0.027、0.002、0.000);照射野数多少与V_PTV-n30~45无关(P=0.438、0.535、0.425、0.313)而与V_PTV-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V_PTV-nx值均大于胸中段及胸下段,且V_PTV-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V_PTV-n40~50则未见显著性差异(P=0.076、0.173、0.695)。V_PTV-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。

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

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 V_x value of upper-thoracic segment was greater than those of middle-and lower-thoracic 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 V_x 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.