三种局部补量技术在晚期宫颈癌放疗中的应用研究

Application of three different kinds of local boost techniques in radiotherapy for locally advanced cervical cancer

目的探讨三维腔内联合组织间插植(IC/IS BT)、三维腔内(ICBT)联合调强(ICBT+IMRT)以及单纯IMRT技术在局部晚期宫颈癌治疗中的剂量学差异。方法选取16例接受三维近距离治疗的局部晚期宫颈癌患者,在原IC/IS BT计划的基础上分别设计ICBT+IMRT和单纯IMRT计划,研究3种计划中肿瘤靶区和危及器官(OARs)的剂量学差异。结果共制定75个后装治疗计划,其中IC/IS BT、ICBT+IMRT和单纯IMRT各25个。ICBT+IMRT与IC/IS BT计划的靶区体积剂量D90差异无统计学意义(P>0.05),OARs的剂量比较低。单纯IMRT计划中OARs受量相对较大,且V60明显偏高(与IC/IS BT相比,t=6.77、10.37、4.61、2.83,P<0.05)。结论ICBT+IMRT计划的肿瘤靶区剂量覆盖较好且OARs受剂量低,可以作为IC/IS BT替代治疗手段。单纯IMRT技术虽然靶区覆盖度较好,但OARs保护差,不适用于晚期宫颈癌的局部补量治疗。

Objective To investigate the dosimetry differences in the treatment of locally advanced cervical cancer with intracavitary/interstitial brachytherapy(IC/IS BT),intracavity brachytherapy combined with intensity modulated radiotherapy(ICBT+IMRT)and simple IMRT.Methods Totally 16 patients with local advanced cervical cancer were retrospectively selected,which were treated by three-dimensional brachytherapy.On the basis of the original three-dimensional intracavitary/interstitial brachytherapy plan,ICBT+IMRT and IMRT plans were designed respectively to study the dosimetry differences of target and different organs at risk for the three kinds of plans.Results A total of 75 brachytherapy treatment plans were designed,including 25 IC/IS BT,25 ICBT+IMRT and 25 IMRT.There was not statistically significant difference of target dose parameters between ICBT+IMRT and IC/IS BT plan(P>0.05).ICBT+IMRT plans had better OAR sparing than IC/IS BT.The doses of OARs in the IMRT plans were relatively large and the volume irradiated to more than 60 Gy(V60)was significantly higher(t=6.77,10.37,4.61,2.83,P<0.05).Conclusions The ICBT+IMRT technique not only provides better target coverage,but also maintains low doses to the OARS,which can be used as an alternative treatment to IC/IS BT.Although the target coverage of IMRT is better,the protection of OARs is not satisfied,so it is not suitable for local boost therapy of advanced cervical cancer.