早期乳腺癌保乳术后加速部分乳腺调强放疗与全乳腺同步推量调强放疗的剂量学比较

Dosimetric comparison of accelerated partial breast irradiation and whole breast irradiation with simultaneous integrated boost intensity modulated radiotherapy after breast-conserving surgery for early breast cancer

目的探讨早期乳腺癌保乳术后加速部分乳腺调强放疗(APBI-IMRT)和全乳腺同步推量调强放疗(WBI-SIB-IMRT)的剂量学差异。方法纳入2009年7月至2014年12月吉林省肿瘤医院早期乳腺癌保乳术后放疗患者35例,每例患者进行APBI-IMRT和WBI-SIB-IMRT两个靶区计划设计。运用剂量体积直方图(DVH)评估靶区及正常组织剂量学差异。结果与WBI-SIB-IMRT相比,APBI-IMRT累积放射效应(CRE)校正后术腔大体肿瘤体积(GTVtb)和计划术腔大体肿瘤外扩体积(PGTVtb)剂量差异均无统计学意义(均P>0.05),CRE校正后临床靶体积(CTV)的剂量较高[(4720±71)cGy比(3889±79)cGy,t=3.184,P=0.027],CRE校正后计划靶体积(PTV)的剂量也较高[(4675±164)cGy比(3807±199)cGy,t=2.751,P=0.032]。CRE校正后,与WBI-SIB-IMRT对比,APBI-IMRT患侧肺组织和左侧乳腺癌患者心脏组织的剂量降低[(558.5±8.9)cGy比(1304.9±34.4)cGy,t=-7.328,P=0.001;(35.5±5.3)cGy比(843.0±41.5)cGy,t=-8.137,P=0.001];两种放疗方式间全组患者患侧肺V5/3.6 Gy、V10/7.3 Gy、V15/10.9 Gy、V20/14.6 Gy、V25/18.2 Gy、V30/21.9 Gy及左侧乳腺癌患者心脏V30/21.9 Gy和V40/29.2 Gy差异均有统计学意义(均P=0.001)。结论与WBI-SIB-IMRT相比,APBI-IMRT改善了靶区剂量的分布,减少了危及器官高剂量受照体积。

Objective To compare the dosimetric differences between accelerated partial breast irradiation intensity modulated radiation therapy(APBI-IMRT)and whole breast irradiation with simultaneous integrated boost intensity modulated radiotherapy(WBI-SIB-IMRT)for early-stage breast cancer after breast-conserving surgery.Methods A total of 35 patients with early-stage breast cancer in Jilin Province Cancer Hospital between July 2009 and December 2014 after breast-conserving surgery were enrolled.The targeted regions of APBI-IMRT and WBI-SIB-IMRT were created for each patient.The dosimetric difference comparison of the targeted region and normal tissues was evaluated by using dose volume histogram(DVH).Results There was no significant difference in the dosimetric comparison of gross tumor volume(GTVtb)and planning gross tumor volume(PGTVtb)after correction of cumulative radiation effect(CRE)between WBI-SIB-IMRT group and APBI-IMRT group(both P>0.05).The dose of clinical target volume(CTV)and planning target volume(PTV)in APBI-IMRT group was higher than that in WBI-SIB-IMRT group[CTV:(4720±71)cGy vs.(3889±79)cGy,t=3.184,P=0.027;PTV:(4675±164)cGy vs.(3807±199)cGy,t=2.751,P=0.032]after CRE correction.Compared with WBI-SIB-IMRT group,the dose of ipsilateral lung tissue and left heart tissue in APBI-IMRT group was decreased after CRE correction[(558.5±8.9)cGy vs.(1304.9±34.4)cGy,t=-7.328,P=0.001;(35.5±5.3)cGy vs.(843.0±41.5)cGy,t=-8.137,P=0.001].V5/3.6 Gy,V10/7.3 Gy,V15/10.9 Gy,V20/14.6 Gy,V25/18.2 Gy and V30/21.9 Gy of the ipsilateral lung and V30/21.9Gy,V40/29.2Gy of left heart in all breast cancer patients after two chemotherapy treatments had significant differences(all P=0.001).Conclusion Compared with WBI-SIB,APBI-IMRT can improve the dose distribution in target area and reduce the volume of high dose irradiation in organs at risk.