3D-CRT中采用二程计划对局部晚期食管癌患者V20及放射性肺炎的影响

Impact of 3D-CRT using two-process plan on V20 and incidence of radioactive pneumonia in patients with locally advanced esophageal cancer

目的探讨局部晚期食管癌适形放疗中采用二程计划对V20(肺接受>20 Gy照射的体积占全肺体积百分比)和放射性肺炎(radioactive pneumonia,RP)的影响。方法 40例局部晚期食管癌患者,随机分为一次计划放疗组20例(A组)和二程计划放疗组20例(B组),所有患者均接受三维适形放疗,诱导化疗前行首次CT定位,A组制定全程适形计划,给予处方剂量66 Gy,B组放疗剂量达到46 Gy后,行第2次CT定位,将2次CT图像融合,制定后程适形计划,给予处方剂量20 Gy,总处方剂量66 Gy。计算并比较两组放疗计划中V20、放疗结束3月内RP发生情况。结果 40例患者中RP发生率为22.5%(9/40),其中A组7例(35.0%),B组2例(10.0%),二次定位双侧肺V20差异有统计学意义(P<0.05),双侧肺平均受照剂量差异无统计学意义(P>0.05)。结论在局部晚期食管癌适形放疗中,宜采用分程放疗,从而降低肺受量,降低放射性肺损伤的发生率。

Objective To investigate the impact of three-dimensional conformal radiotherapy using two-process plan on V20 and the incidence of radioactive pneumonia （ RP ） in patients with locally advanced esophageal cancer. Methods Forty patients with locally advanced esophageal cancer undergoing three-dimensional conformal radiotherapy were randomly assigned to use one-process plan （group A, n = 20） or two-process plan （group B, n = 20）. First CT positioning was performed before inductive chemotherapy in all patients. For patients in group A an entire dose of 66 Gy was given. For patients in group B, when the dose reached 46 Gy, the second row CT positioning was perfornled and the two CT images were fused; the late course eonformal planning was formed and 20 Gy dose was prescribed with a total dose of 66 Gy. The V20 was calculated and the incidence of RP over three months was documented in two groups. Results The overall incidence of RP was 22.5% （ 9/40）, including 7 cases in group A （ 35.0% ） and 2 cases in group B （ 10.0% ）. There was significant difference in bilateral lung V20 between two positionings （ P 〈 0.05 ）, but no difference in bilateral lung average illuminated dose （ P 〉 0.05 ）. Conclusion Adoption of two-process plan for couformal radiotherapy can reduce lung V20 and incidence of radiation-induced lung injury for patients with locally advanced esophageal cancer.