Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, 1184 5th Avenue, Box 1236, New York, NY, 10029, USA.
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Radiat Oncol. 2018 Sep 24;13(1):187. doi: 10.1186/s13014-018-1132-9.
Despite dosimetric benefits of volumetric modulated arc therapy (VMAT) in breast cancer patients with implant reconstruction receiving regional nodal irradiation (RNI), low dose to the thoracic structures remains a concern. Our goal was to report dosimetric effects of adding deep inspiration breath hold (DIBH) to VMAT in left-sided breast cancer patients with tissue expander (TE)/permanent implant (PI) reconstruction receiving RNI.
Ten consecutive breast cancer patients with unilateral or bilateral TE/PI reconstruction who were treated with a combination of VMAT and DIBH to the left reconstructed chest wall and regional nodes were prospectively identified. Free breathing (FB) and DIBH CT scans were acquired for each patient. VMAT plans for the same arc geometry were compared for FB versus DIBH. Prescription dose was 50 Gy in 25 fractions. Dosimetric differences were tested for statistical significance.
For comparable coverage and target dose homogeneity, the mean dose to the heart reduced on average by 2.9 Gy (8.2 to 5.3 Gy), with the addition of DIBH (p < 0.05). The maximum dose to the left anterior descending (LAD) artery was reduced by 9.9 Gy (p < 0.05), which related closely to the reduction in the maximum heart dose (9.4 Gy). V05 Gy to the heart, ipsilateral lung, contralateral lung and total lung (p < 0.05) decreased on average by 29.6%, 5.8%, 15.4% and 10.8% respectively. No significant differences were seen in the ipsilateral lung V20 Gy or mean dose as well as in the mean contralateral breast/implant dose. However, V04 Gy and V03 Gy of the contralateral breast/implant were respectively reduced by 13.2% and 18.3% using DIBH (p < 0.05).
Combination of VMAT and DIBH showed significant dosimetric gains for low dose to the heart, lungs and contralateral breast/implant. Not surprisingly, the mean and maximum dose to the heart and to the LAD were also reduced. DIBH should be considered with the use of VMAT in breast cancer patients with implant reconstructions receiving RNI.
尽管容积调强弧形治疗（VMAT）在接受区域淋巴结照射（RNI）的植入物重建乳腺癌患者中有剂量学优势，但胸部结构的低剂量仍然是一个问题。我们的目标是报告在接受 RNI 的左侧乳腺癌患者中，使用深吸气屏气（DIBH）添加到 VMAT 中的剂量学效应，这些患者接受了组织扩张器（TE）/永久性植入物（PI）重建。
前瞻性地确定了 10 例接受左侧重建胸壁和区域淋巴结 VMAT 和 DIBH 联合治疗的单侧或双侧 TE/PI 重建的连续乳腺癌患者。为每位患者采集自由呼吸（FB）和 DIBH CT 扫描。比较 FB 与 DIBH 时相同弧形几何形状的 VMAT 计划。处方剂量为 50Gy，分为 25 个分数。测试了剂量学差异的统计学意义。
为了获得可比的覆盖范围和靶剂量均匀性，平均心脏剂量平均降低了 2.9Gy（8.2 至 5.3Gy），添加 DIBH 后（p<0.05）。左前降支（LAD）动脉的最大剂量降低了 9.9Gy（p<0.05），这与最大心脏剂量的降低密切相关（9.4Gy）。心脏、同侧肺、对侧肺和全肺的 V05Gy（p<0.05）平均降低了 29.6%、5.8%、15.4%和 10.8%。同侧肺 V20Gy 或平均剂量以及对侧乳房/植入物的平均剂量无显著差异。然而，使用 DIBH 时，对侧乳房/植入物的 V04Gy 和 V03Gy 分别降低了 13.2%和 18.3%（p<0.05）。
VMAT 和 DIBH 的组合为心脏、肺和对侧乳房/植入物的低剂量显示出显著的剂量学增益。毫不奇怪，心脏和 LAD 的平均和最大剂量也降低了。在接受 RNI 的接受植入物重建的乳腺癌患者中，应考虑使用 VMAT 和 DIBH。
