Yuan Jianling, Lee Richard, Dusenbery Kathryn Ellen, Lee Chung K, Mathew Damien C, Sperduto Paul Wayne, Watanabe Yoichi
Department of Radiation Oncology, University of Minnesota Medical School, University of Minnesota, Minneapolis, MN, United States.
University of Minnesota Medical Center-Fairview Gamma Knife Center, University of Minnesota, Minneapolis, MN, United States.
Front Oncol. 2018 Mar 13;8:65. doi: 10.3389/fonc.2018.00065. eCollection 2018.
Repeat stereotactic radiosurgery (SRS) is an attractive alternative to whole brain radiation therapy (WBRT) for treatment of recurrent brain metastases (BM). The purpose of this study is to determine the cumulative doses to the brain and critical normal structures in patients who underwent repeat courses of Gamma Knife (GK) SRS.
We retrospectively identified ten patients who received at least three GK-SRS sessions for multiply recurrent BM at our institution from 2013 to 2016. We used Velocity™ 3.1.0 software to co-register the magnetic resonance imaging images and the dose data of all treatment sessions for each patient. The cumulative doses to brain, lenses, eyes, brainstem, optic nerves, chiasm, and hippocampi were calculated. Dose-volume histograms, as well as the mean, median and maximum doses of these structures, were analyzed.
The median number of SRS was five sessions (range = 3-7 sessions) per patient over a median treatment span of 510 days (112-1,197 days), whereas the median number of metastatic tumors treated per patient was 25.0 (10-63). The median of the total tumor volume was 9.5 cc (2.3-75.9 cc). The median of the mean cumulative dose to the whole brain was 4.1 Gy (1.7-16.4 Gy). The medians of the maximum doses to the critical structures were as follows: brainstem, 6.1 Gy (2.2-28.9 Gy), chiasm, 3.9 Gy (1.8-10.8 Gy), right optic nerve, 2.9 Gy (1.2-9.0 Gy), and left optic nerve, 2.6 Gy (1.0-6.5 Gy). The medians of the mean and maximum cumulative doses to the hippocampi were 3.4 Gy (1.0-14.4 Gy) and 13.8 Gy (1.5-39.3 Gy), respectively. The median survival for the entire cohort was 26.7 months, and no patients developed radiation necrosis.
Our study demonstrated that multisession GKSRS could be delivered with low cumulative doses to critical normal structures. Further studies are required to fully establish its role as an alternative treatment strategy to WBRT for the treatment of multiply recurrent BM.
对于复发性脑转移瘤（BM）的治疗，重复立体定向放射外科治疗（SRS）是全脑放射治疗（WBRT）的一个有吸引力的替代方案。本研究的目的是确定接受伽玛刀（GK）SRS重复疗程的患者脑部及关键正常结构的累积剂量。
我们回顾性地确定了2013年至2016年在我们机构接受至少三次GK-SRS治疗多发性复发性BM的10例患者。我们使用Velocity™ 3.1.0软件对每位患者所有治疗疗程的磁共振成像图像和剂量数据进行配准。计算脑部、晶状体、眼睛、脑干、视神经、视交叉和海马体的累积剂量。分析剂量体积直方图以及这些结构的平均、中位和最大剂量。
每位患者SRS的中位次数为5次（范围=3 - 7次），中位治疗跨度为510天（112 - 1197天），而每位患者治疗的转移瘤中位数量为25.0个（10 - 63个）。肿瘤总体积的中位数为9.5 cc（2.3 - 75.9 cc）。全脑平均累积剂量的中位数为4.1 Gy（1.7 - 16.4 Gy）。关键结构最大剂量的中位数如下：脑干，6.1 Gy（2.2 - 28.9 Gy），视交叉，3.9 Gy（1.8 - 10.8 Gy），右侧视神经，2.9 Gy（1.2 - 9.0 Gy），左侧视神经，2.6 Gy（1.0 - 6.5 Gy）。海马体平均和最大累积剂量的中位数分别为3.4 Gy（1.0 - 14.4 Gy）和13.8 Gy（1.5 - 39.3 Gy）。整个队列的中位生存期为26.7个月，且无患者发生放射性坏死。
我们的研究表明，多疗程GK-SRS可以以低累积剂量给予关键正常结构。需要进一步研究以充分确立其作为WBRT替代治疗策略用于治疗多发性复发性BM的作用。
