Department for Radiation Oncology, University of Leipzig Medical Center, Stephanstr. 9a, 04103, Leipzig, Germany.
Departement of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Strahlenther Onkol. 2021 Aug;197(8):674-682. doi: 10.1007/s00066-020-01707-8. Epub 2020 Nov 23.
Several studies have demonstrated the negative impact of radiotherapy protocol deviations on tumor control in medulloblastoma. In the SIOP PNET5 MB trial, a pretreatment radiotherapy quality control (RT-QC) program was introduced. A first analysis for patients enrolled in Germany, Switzerland and Austria with focus on types of deviations in the initial plan proposals and review criteria for modern radiation technologies was performed.
Sixty-nine craniospinal irradiation (CSI) plans were available for detailed analyses. RT-QC was performed according to protocol definitions on dose uniformity. Because of the lack of definitions for high-precision 3D conformal radiotherapy within the protocol, additional criteria for RT-QC on delineation and coverage of clinical target volume (CTV) and planning target volume (PTV) were defined and evaluated.
Target volume (CTV/PTV) deviations occurred in 49.3% of initial CSI plan proposals (33.3% minor, 15.9% major). Dose uniformity deviations were less frequent (43.5%). Modification of the RT plan was recommended in 43.5% of CSI plans. Unacceptable RT plans were predominantly related to incorrect target delineation rather than dose uniformity. Unacceptable plans were negatively correlated to the number of enrolled patients per institution with a cutoff of 5 patients (p = 0.001).
This prospective pretreatment individual case review study revealed a high rate of deviations and emphasizes the strong need of pretreatment RT-QC in clinical trials for medulloblastoma. Furthermore, the experiences point out the necessity of new RT-QC criteria for high-precision CSI techniques.
多项研究表明，放疗方案偏差对髓母细胞瘤的肿瘤控制有负面影响。在 SIOP PNET5 MB 试验中，引入了一种预处理放疗质量控制（RT-QC）程序。对在德国、瑞士和奥地利入组的患者进行了首次分析，重点关注初始计划建议中的偏差类型和现代放射技术的审查标准。
共有 69 例颅脊髓照射（CSI）计划可进行详细分析。根据协议定义，对剂量均匀性进行 RT-QC。由于协议中缺乏高精度 3D 适形放疗的定义，因此定义并评估了用于靶区（CTV 和 PTV）勾画和覆盖的额外 RT-QC 标准。
49.3%的初始 CSI 计划建议中存在靶区（CTV/PTV）偏差（33.3%为轻微偏差，15.9%为主要偏差）。剂量均匀性偏差较少（43.5%）。43.5%的 CSI 计划建议修改 RT 计划。不可接受的 RT 计划主要与靶区勾画不正确有关，而不是剂量均匀性。不可接受的计划与每个机构入组的患者数量呈负相关，截定点为 5 例（p=0.001）。
这项前瞻性预处理个体病例回顾研究显示偏差发生率较高，强调了髓母细胞瘤临床试验中预处理 RT-QC 的强烈需求。此外，这些经验指出需要针对高精度 CSI 技术制定新的 RT-QC 标准。
