调强放疗与常规放疗应用于早期左侧乳腺癌保乳术后患者的剂量学及心功能比较

Comparison of dosimetry and cardiac function between intensity-modulated radiotherapy and conventional radiotherapy in patients with early left breast cancer after breast-conserving surgery

目的比较调强放疗与常规放疗应用于早期左侧乳腺癌保乳术后患者的剂量学变化,分析调强放疗对心功能的影响。方法2016年4月至2017年3月接受保乳术治疗的76例早期乳腺癌患者,根据病情评估及患者意愿分为调强放疗组36例及常规放疗组40例。两组计划靶区剂量50 Gy/25次,瘤床推量10 Gy/5次。比较两组计划靶区剂量、危险器官剂量、肌钙蛋白、心功能等指标。结果放疗后,调强放疗组V 100%、V 105%、V 110%、均匀性指数低于常规放疗组,适应性指数高于常规放疗组;患侧肺平均剂量与V 20%、对侧肺Dmea、心脏Dmea与V 40%及肌钙蛋白含量低于常规放疗组,左心房收缩末期内径、左心室舒张末期内径、射血分数、短轴缩短率高于常规放疗组,差异均有统计学意义(P<0.05)。结论调强放疗能够调节靶区照射剂量的均匀性与适应性,减少心肺正常组织照射体积与照射剂量,抑制心脏功能受损程度。

Objective To compare the dosimetric changes between intensity modulated radiotherapy(IMR)and conventional radiotherapy in patients with early left breast cancer after breast conserving surgery,and to analyze the effect of IMR on cardiac function.Methods Seventy-six patients with early breast cancer who received breast conserved surgery from April 2016 to March 2017 were divided into intensity modulated radiotherapy group(n=36)and conventional radiotherapy group(n=40)according to their condition evaluation and willingness.The planned target area dose was 50 gy/25 times,and tumor bed volume was 10 gy/5 times in both groups.The target dose,risk organ dose,troponin and cardiac function were compared between the two groups.Results After radiotherapy,the V100%,V105%,V110%and homogeneity index(HI)were lower and the adaptability index(CI)was higher in the intensity modulated radiotherapy group than those of the conventional radiotherapy group.The average dose of affected lung and V 20%,average dose of contralateral lung,average dose of heart and V 40%as well as troponin content were lower in the intensity modulated radiotherapy group than those in the conventional radiotherapy group.The left atrial end-systolic diameter(LADs),end-diastolic diameter(LVDd),ejection fraction(EF)and short axis shortening fraction(FS)of the left atrium in the intensity modulated radiotherapy group were higher than those of the conventional radiotherapy group.All the differences were statistically significant(P<0.05).Conclusion The intensity modulated radiotherapy can adjust the radiation dose uniformity and adaptability in the target area,reduce the irradiation volume and dose of normal cardiopulmonary tissue,and inhibit the degree of cardiac function damage.