National Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, Northwood, United Kingdom.
National Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, Northwood, United Kingdom.
Pract Radiat Oncol. 2018 Jul-Aug;8(4):e212-e220. doi: 10.1016/j.prro.2017.12.011. Epub 2017 Dec 30.
Stereotactic radiosurgery is indicated for treatment of multiple brain metastases. Various treatment platforms are available, but most comparisons are limited to single-center studies. As part of a national commissioning program, benchmark planning cases were completed by 21 clinical centers, providing a unique dataset of current practice across a large number of providers and equipment platforms.
Two brain metastases cases were provided, with images and structures predrawn, involving 3 and 7 lesions. Centers produced plans according to their local practice, which were reviewed centrally using metrics for target coverage, selectivity, gradient fall-off, and normal tissue sparing.
Fifty plans were submitted, using 24 treatment platforms. Eleven plans were revised following feedback, including 2 centers that acquired a new platform; 1 other center accepted a restriction of service. All centers prioritized coverage, with the prescription isodose covering ≥95% of 233 of 235 target volumes. Selectivity was much more variable, especially for smaller lesions, and when combined with poor gradient indices resulted in large volumes of normal tissue being irradiated. Tomotherapy submissions were outliers for either selectivity or gradient index, but other platforms could produce plans with relatively low gradient indices for larger lesion volumes. There was more variation among Varian and Elekta LINAC plans than for Gamma Knife and CyberKnife, and larger differences for smaller targets, both inter- and intratreatment platform. Doses to normal brain and brainstem were highest when margins were applied, but improvements were possible by replanning alone.
Multicenter benchmarking exercises have highlighted some variation in clinical practice and priorities, with a few outliers. Most platforms are able to achieve comparable plans, except for the smallest volumes and when larger planning margins are used. The data will be used to advance standardization and quality improvement of national services and can provide useful guidance for centers worldwide.
立体定向放射外科适用于治疗多发脑转移瘤。有多种治疗平台可供选择，但大多数比较仅限于单中心研究。作为国家委托计划的一部分，21 个临床中心完成了基准计划病例，为大量提供者和设备平台提供了当前实践的独特数据集。
提供了两个脑转移病例，图像和结构已预先绘制，涉及 3 个和 7 个病变。中心根据当地实践制定计划，这些计划由中央使用目标覆盖、选择性、梯度下降和正常组织保护的指标进行审查。
提交了 50 份计划，使用了 24 种治疗平台。11 份计划在反馈后进行了修订，包括 2 个中心获得了新的平台；另一个中心接受了服务限制。所有中心都优先考虑覆盖范围，处方等剂量线覆盖了 235 个目标体积中的 233 个，占比≥95%。选择性差异较大，特别是对于较小的病变，并且与较差的梯度指数结合使用会导致大量正常组织受到照射。托姆治疗提交的结果在选择性或梯度指数方面是异常值，但其他平台可以为较大的病变体积生成具有相对较低梯度指数的计划。瓦里安和 Elekta LINAC 计划之间的差异比伽玛刀和 CyberKnife 更大，对于较小的靶标，无论是在治疗平台之间还是内部，差异都更大。当应用边缘时，正常大脑和脑干的剂量最高，但单独重新计划可以有所改善。
多中心基准测试强调了临床实践和优先级的一些差异，其中有一些异常值。除了最小的体积和使用较大的计划边缘时，大多数平台都能够实现可比的计划。该数据将用于推进国家服务的标准化和质量改进，并为全球中心提供有用的指导。
