早期宫颈癌部分子宫照射的物理剂量学研究

A dosimetric study of partial uterine-radiotherapy in early stage cervical cancer

目的探索宫颈癌根治性同期放化疗中部分子宫照射对减少盆腔正常脏器剂量的意义。方法选取2014年10月至2016年10月在汕头大学医学院附属肿瘤医院接受根治性放化疗的20例宫颈癌患者,为每个患者设计2套放疗计划:(1)全子宫照射:临床靶区(CTV)包括完整子宫;(2)部分子宫照射:CTV包括肿瘤靶区(GTV)以外10mm的子宫组织。比较每个患者2组放疗计划的参数和盆腔正常器官受照射剂量。结果部分子宫照射和全子宫照射适形度和均匀度差异无统计学意义;部分子宫照射的计划靶区(PTV)体积为(1 065±134)cm^3,小于全子宫照射的PTV体积(1 141±133)cm^3(P=0.00);部分子宫照射能减少部分盆腔脏器受照剂量:部分子宫照射膀胱V45=(27±9)%,全子宫照射V45=(32±11)%(P=0.01);部分子宫照射直肠V40=(84±9)%,全子宫照射直肠V40=(86±9)%(P=0.01);部分子宫照射小肠V45=(76±53)cm^3,全子宫照射小肠V45=(79±56)cm^3(P=0.03)。结论部分子宫照射能减少PTV体积,并减少部分盆腔正常器官受照射剂量,但所减少的绝对体积较小,临床意义不大。

Objective To investigate the normal tissue doses resulting from the definitive partial uterine-radiotherapy in cervical cancer.Methods Twenty patients with cervical cancer had treatment planning with normal radiotherapy（RT）including the whole uterus in CTV（Plan A）and partial uterus（Plan B;CTV：GTV with 10 mm margin）.The treatment parameters and dose-volume histogram data for the different plans were compared.Results All of the plans generated similar dose distributions and conformity index.The volume of PTV Vwas（1 065±134）cm^3 in Plan B and（1 141±133）cm^3 in Plan A（P =0.00）.The Plan B yielded significantly lower bladder V45=（27±9）%,rectum V40=（84±9）%and intestinal V45=（76±53）cm^3 compared with Plan A bladder V45=（32±11）%,rectum V40=（86±9）% and intestinal V45=（79±56）cm^3,respectively.ConclusionThe Plan B appeared to spare the normal tissue from irradiation area.However,no significant clinical improvement can be translated from the dose differences.