在左侧乳腺癌内乳链照射的乳房切除术后放疗中，采用固定辅助的腹部深吸气屏气技术。
Immobilization-assisted abdominal deep inspiration breath-hold in post-mastectomy radiotherapy of left-sided breast cancer with internal mammary chain coverage.
作者信息
Chen Meiqin, Zang Shoumei, Yu Hao, Ning Lihua, Huang Huijie, Bu Luyi, Ge Jia, Xu Mengyou, Tang Qiuying, Zhao Feng, Yao Guorong, Yan Senxiang
机构信息
Department of Radiation Oncology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou and Department of Radiation Oncology, Affiliated Jinhua Hospital, College of Medicine, Zhejiang University, Jinhua, China.
Department of Radiation Oncology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
出版信息
Quant Imaging Med Surg. 2021 Jul;11(7):3314-3326. doi: 10.21037/qims-20-831.
BACKGROUND
Whether to prophylactically irradiate the ipsilateral internal mammary chain (IMC) in post-mastectomy radiotherapy (PMRT) remains controversial because of equivocal clinical benefits against the added toxicities. Our previous study revealed that the cardiac dose was decreased during left-sided breast radiotherapy with abdominal deep inspiration breath-hold (aDIBH) as compared with free-breathing (FB) and thoracic deep inspiration breath-hold (tDIBH). Here we present the dosimetric advantage of aDIBH for patients undergoing PMRT with IMC coverage.
METHODS
We prospectively analyzed 19 patients with left-sided breast cancer who underwent PMRT. Patients underwent computed tomography (CT) simulation under both free-breathing (FB) and aDIBH. The heart, left anterior descending coronary artery (LAD), lungs, and the contralateral breast was defined as organs at risk (OARs). Three-dimensional conformal radiation therapy (3D-CRT), inverse planning intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT) were used to calculate the doses received by both the planning target volume (PTV) and OARs, which were compared using the Wilcoxon signed-rank test.
RESULTS
Compared with FB, the D of the heart and LAD were respectively reduced by 3.5 Gy (P<0.003) and 8.9 Gy (P<0.001) in 3D-CRT, 2.6 Gy (P<0.001), and 7.8 Gy (P=0.001) in IMRT, 1.5 Gy (P<0.001) and 4.5 Gy (P=0.001) in VMAT plans under aDIBH. Among all these plans, the D of the heart was lowest in aDIBH and 1.3 Gy lower than in aDIBH (P=0.002). aDIBH also resulted in a significantly reduced dose to the ipsilateral lung than plans under FB (P<0.05). D and V5 to the contralateral lung and breast were higher in VMAT plans (P<0.05).
CONCLUSIONS
Using an immobilization-assisted aDIBH technique, radiation doses to the heart can be kept at reasonably low levels even if IMC is included in the clinical target volume (CTV). Among 3D-CRT, IMRT, and VMAT plans, IMRT plus aDIBH results in the best heart-sparing effect. We recommend that the aDIBH technique be routinely applied in suitable patients if the IMC is irradiated.
背景
在乳房切除术后放疗（PMRT）中，是否对同侧内乳链（IMC）进行预防性照射仍存在争议，因为其临床益处与增加的毒性尚不明确。我们之前的研究表明，与自由呼吸（FB）和胸部深吸气屏气（tDIBH）相比，左侧乳腺癌放疗期间采用腹部深吸气屏气（aDIBH）时心脏剂量降低。在此，我们展示了aDIBH对接受IMC覆盖的PMRT患者的剂量学优势。
方法
我们前瞻性分析了19例接受PMRT的左侧乳腺癌患者。患者在自由呼吸（FB）和aDIBH两种状态下进行计算机断层扫描（CT）模拟。将心脏、左前降支冠状动脉（LAD）、肺和对侧乳房定义为危及器官（OARs）。采用三维适形放射治疗（3D-CRT）、逆向计划调强放射治疗（IMRT）和容积调强弧形治疗（VMAT）来计算计划靶体积（PTV）和OARs所接受的剂量，并使用Wilcoxon符号秩检验进行比较。
结果
与FB相比，在aDIBH下，3D-CRT中心脏和LAD的剂量分别降低了3.5 Gy（P<0.003）和8.9 Gy（P<0.001），IMRT中分别降低了2.6 Gy（P<0.001）和7.8 Gy（P=0.001），VMAT计划中分别降低了1.5 Gy（P<0.001）和4.5 Gy（P=0.001）。在所有这些计划中，aDIBH下心脏剂量最低，比FB下低1.3 Gy（P=0.002）。aDIBH也使同侧肺所接受的剂量比FB下的计划显著降低（P<0.05）。VMAT计划中对侧肺和乳房的D和V5更高（P<0.05）。
结论
使用固定辅助的aDIBH技术，即使IMC包含在临床靶体积（CTV）中，心脏的放射剂量也可保持在合理的低水平。在3D-CRT、IMRT和VMAT计划中，IMRT加aDIBH产生的心脏保护效果最佳。我们建议，如果对IMC进行照射，aDIBH技术应常规应用于合适的患者。
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