乳腺癌根治术后放疗中腋窝危及器官的勾画与限量研究

Delineation and Dose Limitation of Axillary Organ at Risk During Breast Cancer Postoperative Radiotherapy

[目的]探讨在乳腺癌根治术后放疗中勾画腋窝危及器官(OAR腋窝)并对其进行剂量限制的可行性,以期为降低放疗所致上肢淋巴水肿风险提供剂量学证据。[方法]回顾性选择26例乳腺癌根治术后患者,针对每例患者采用标准及改进方法分别勾画腋窝OAR(OARS、OARM),每例患者分别设计4套治疗计划:OAR腋窝限量与不限量的3D-CRT计划(CRTlimit、CRT)、OAR腋窝限量与不限量的IMRT计划(IMRTlimit、IMRT)。评估两种勾画方法所得到的OARS与OARM之间解剖位置关系和剂量学差异性,以及腋窝OAR限量后OAR腋窝的剂量获益以及对靶区和其他OAR的剂量学影响。[结果]基于两种方法所勾画的腋窝OAR(OARS、OARM)体积分别为20.9 cm^(3)和23.6 cm^(3)(P=0.000),CI和DSC分别为0.79、0.88。除了CRT计划中的Dmin以外,两者无剂量学差异(P>0.05)。在CRT和IMRT计划中,OAR腋窝限量显著性降低了其剂量,其中Dmin分别降低了13.9%和27.2%,分别为34.0 Gy、30.3 Gy。OAR腋窝限量后靶区和其他OAR无本质上的剂量学差异。[结论]在乳腺癌根治术后放疗中针对腋窝OAR的勾画以及剂量限制是可行的,Dmin<36.8 Gy可作为腋窝危及器官的限量标准,推荐采用改进方法勾画。

[Objective]To explore the feasibility of delineating the axillary organ at risk(OARaxilla)and limiting its dose during breast cancer postoperative radiotherapy in order to provide dosimetric evidence for reducing the risk of breast cancer-related lymphedema caused by radiotherapy.[Methods]Twenty-six patients after modified radical mastectomy for breast cancer were selected retrospectively.For each patient,delineate the axillary OAR(OARS,OARM)using standard and modified methods.Four treatment plans were designed for each patient:OARaxillalimited and unlimited 3D-CRT plans(CRTlimit,CRT),OARaxillalimited and unlimited IMRT plans(IMRTlimit,IMRT).To evaluate the anatomical position relationship and dosimetric difference between OARSand OARMobtained by the two methods,as well as the dose benefit of OARaxillaafter axillary OAR limited and the dosimetric effect on the target area and other OARS.[Result]The volume of the axillary OAR(OARS,OARM)based on the two methods were 20.9 cm3and 23.6 cm^(3)(P=0.000),and CI and DSC were 0.79,0.88.Except for Dminin the CRT plan,there were no dosimetric differences between the two(P>0.05).In the CRT and IMRT plans,the OARaxillalimit significantly reduced its dose,of which Dminwas reduced by 13.9%and 27.2%,respectively,to 34.0 Gy and 30.3 Gy.There was no dosimetric difference between the target area and other OARSafter the OARaxillalimit.[Conclusion]It is feasible to delineate and limit the dose of the axillary OAR during breast cancer postoperative radiotherapy.Dmin<36.8 Gy can be used as the limited standard of axillary OAR,and the modified delineation method is recommended.