臂丛神经在乳腺癌术后锁骨上下淋巴引流区放射治疗的三维剂量学研究

Dosimetric Evaluation of Brachial Plexus with Supraclavicular Irradiation for Breast Cancer

目的:探讨臂丛神经在乳腺癌术后锁骨上下淋巴引流区放射治疗中的剂量学特点及其受照射剂量与患者体格特征之间的潜在关系。方法:选取31例乳腺癌中晚期乳腺癌根治术后患者,依据放射治疗肿瘤协作组中相关规定勾画出臂丛神经,运用Pinnacle 8.6计划系统为每例患者设计放射治疗计划,处方剂量为5000 cGy/25次。结果:锁骨上下淋巴引流区照射时臂丛神经接受的平均剂量(D mean)较不行锁骨上下淋巴引流区时照射明显增加(4439.22 cGy±413.36 cGy和97.12cGy±19.95 cGy,t=136.746,P=0.00);接受大于4000 cGy、4500 cGy、5000 cGy和5250 cGy所占体积百分比分别为79.287%±10.737%、68.22%±12.63%、49.25%±16.58%和28.52%±18.98%。臂丛神经所接受D mean与EUD显著相关(r=0.966,P=0.000);最大剂量与患者身体指数BMI(r=-0.435,P=0.014)、体重(r=-0.450,P=0.011)和年龄(r=-0.398,P=0.026)均呈负相关。结论:臂丛神经所接受的剂量主要由锁骨上下淋巴引流区照射所造成的;体型偏瘦、年龄越小的患者,臂丛神经接受的最大点剂量偏高。

Objective： To evaluate brachial plexus dose with supraclavicular irradiation and the relation between dose and physical characteristics of patients. Methods： According to the standardized Radiation Therapy Oncology endorsed guidelines delineation, the selected 31 postlumpectomy breast cancer patients were drew the outline ofbrachial plexus. Using Pinnacle 8.6 planning system, Each radiation therapy plan was designed with 5000 cGy for 25 times. Results： With supraclavicular irradiation, the mean dose to brachial plexus was significantly increased（4439.22 cGy±413.36 cGy and 97.12 cGy ±19.95 cGy, t=136.746, P=0.00）, compared to that of without supraclavicular irradiation. The irradiated volume of the brachial plexus receiving 4000 cGy,4500 cGy,5000 cGy and 5250 cGy was 79.287%±10.737%,68.22%±12.63%,49.25%±16.58%,28.52%± 18.98%, respectively. In addition, the mean dose of brachial plexus was obviously correlated with EUD （r=0.966,P=0.000）. The maximum dose of brachial plexus was negatively correlated with body mass index of patients （r=-0.435,P=0.014）, as well as with weight （r=-0.45,P=0.011）.Similarly, an inverse correlation was observed between age and maximum dose（r=-0.398,P=0. 026）. Conclusions： Supraclavicular irradiation was the major reason for the injury of brachial plexus. And the maximum dose of brachial plexus was likely to be higher for thinner、younger patients.