Department of Oncology, Laboratory of Radiation Physics, Odense University Hospital, Odense, Denmark.
Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
Acta Oncol. 2021 Nov;60(11):1425-1431. doi: 10.1080/0284186X.2021.1983209. Epub 2021 Sep 29.
The standard in Denmark for treating breast cancer patients receiving loco-regional irradiation is tangential 3D Conformal RadioTherapy (3DCRT), treated in deep inspiration breath-hold (DIBH). Treating with Volumetric Modulated Arc Therapy (VMAT) may reduce the treatment time, which is particularly important for DIBH treatments. The VMAT should be performed without increased dose to the heart, lung, and contralateral breast. This study compares VMAT and 3DCRT for left-sided breast cancer patients with intramammary lymph node involvement.
Twenty left-sided breast cancer patients were included. VMAT and tangential plans were created for all patients, with a prescription dose of 50 Gy. The tangential plans used 6 MV and for larger breast combined with 18 MV. The VMAT plans utilised two 6 MV fields in a butterfly configuration. Dose planning was done in Pinnacle 16.0 using the Auto-Planning module for the VMAT plans. Comparison of the plans was based on: mean doses, metrics provided by DBCG guidelines, dose-volume histograms and required number of breath-holds for treatment delivery in DIBH.
For most OAR, the doses were similar for VMAT and 3DCRT. The target coverage was comparable, with VMAT having a statistically significant improved dose homogeneity of the target volumes. Less than half the number of breath-hold was required for VMAT compared to 3DCRT. Mean gamma pass rates (3 mm and 3%) from ArcCHECK of the VMAT plans was 98.4% (range 96.6-99.8%).
Automatic VMAT planning of left-sided breast cancer patients with lymph node involvement can produce dose distributions comparable to those of tangential 3DCRT, while reducing the number of breath-holds in DIBH by more than a factor of two. The reduction in breath-holds is beneficial for patient comfort and reduces the risk of intra-fraction patient motion.
丹麦治疗局部区域照射的乳腺癌患者的标准是切线 3D 适形放射治疗（3DCRT），采用深吸气屏气（DIBH）。使用容积调强弧形治疗（VMAT）治疗可能会缩短治疗时间，这对 DIBH 治疗尤为重要。VMAT 应在不增加心脏、肺和对侧乳房剂量的情况下进行。本研究比较了左侧乳腺癌伴内乳淋巴结受累患者的 VMAT 和 3DCRT。
共纳入 20 例左侧乳腺癌患者。为所有患者创建了 VMAT 和切线计划，处方剂量为 50Gy。切线计划使用 6MV，对于较大的乳房，结合使用 18MV。VMAT 计划采用蝶形配置中的两个 6MV 场。在 Pinnacle 16.0 中使用 Auto-Planning 模块进行剂量计划。计划的比较基于：平均剂量、DBCG 指南提供的指标、剂量体积直方图和 DIBH 治疗中所需的屏气次数。
对于大多数 OAR，VMAT 和 3DCRT 的剂量相似。靶区覆盖情况相似，VMAT 具有统计学意义的改善靶区体积剂量均匀性。与 3DCRT 相比，VMAT 所需的屏气次数不到一半。ArcCHECK 对 VMAT 计划的平均伽马通过率（3mm 和 3%）为 98.4%（范围为 96.6-99.8%）。
自动 VMAT 计划治疗左侧乳腺癌伴淋巴结受累患者，可产生与切线 3DCRT 相当的剂量分布，同时将 DIBH 中的屏气次数减少两倍以上。屏气次数的减少有利于患者舒适，降低了分次内患者运动的风险。
