University of California, San Diego, La Jolla, California.
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Int J Radiat Oncol Biol Phys. 2022 Mar 15;112(4):901-912. doi: 10.1016/j.ijrobp.2021.11.016. Epub 2021 Nov 20.
Craniospinal irradiation (CSI) is commonly used for pediatric brain tumors with a propensity for spread in craniospinal fluid, principally medulloblastoma. Evolving technology has led to the use of highly conformal radiation therapy (RT) techniques for CSI, including proton therapy. Target delineation and plan coverage are critical for CSI, but there is ongoing controversy and variability in these realms, with little available data on practice patterns. We sought to characterize proton CSI practice patterns in the United States by examining CSI plans in the Pediatric Proton/Photon Consortium Registry (PPCR).
PPCR was queried for data on proton CSI patients from 2015 to early 2020. Each plan was manually reviewed, determining patient position; prescription dose; and coverage of optic nerves, vertebral bodies, spinal nerve roots, sacral nerves, and cranial foramina, among other variables. Two radiation oncologists blinded to clinical data and treating institution assessed coverage at the 95% prescription isodose line and per published European Society for Paediatric Oncology guidelines. Variability in coverage was assessed with nonparametric tests and univariate and multivariate logistic regression.
PPCR supplied data for 450 patients, 384 of whom had an evaluable portion of a CSI plan. Most patients (90.3%) were supine. Optic nerves were fully covered in 48.2%; sacral nerves in 87.7%; cranial foramina in 69.3%; and spinal nerves in 95.6%. Vertebral body (VB) sparing was used in 18.6% of skeletally immature cases, increasing over time (P < .001). Coverage in all categories was significantly different among treating institutions, on univariate and multivariate analyses. Cribriform plate deficits were rare, with marginal misses of the foramen ovale (17.4%) and frontal lobe (12%) most common.
We found consistent variation based on treating institution in proton CSI practices including optic nerve, VB, sacral nerve, cranial, and spinal nerve coverage. These data may serve as a baseline quantification of current proton CSI practices in the United States as they continue to evolve.
颅脊髓照射（CSI）常用于具有脑脊液体传播倾向的小儿脑肿瘤，主要是髓母细胞瘤。不断发展的技术已经导致使用高度适形的放射治疗（RT）技术进行 CSI，包括质子治疗。靶区勾画和计划覆盖对于 CSI 至关重要，但在这些领域存在持续的争议和可变性，关于实践模式的可用数据很少。我们通过检查小儿质子/光子联合研究组（PPCR）中的 CSI 计划，旨在描述美国质子 CSI 的实践模式。
从 2015 年到 2020 年初，对 PPCR 中的质子 CSI 患者数据进行了查询。手动审查了每个计划，确定了患者的位置；处方剂量；以及视神经、椎体、脊神经根、骶神经和颅孔的覆盖范围，以及其他变量。两名对临床数据和治疗机构均不知情的放射肿瘤学家根据 95%处方等剂量线和已发表的欧洲小儿肿瘤学会指南评估了覆盖范围。使用非参数检验和单变量及多变量逻辑回归评估了覆盖范围的可变性。
PPCR 提供了 450 名患者的数据，其中 384 名患者有 CSI 计划的可评估部分。大多数患者（90.3%）仰卧位。视神经完全覆盖 48.2%；骶神经 87.7%；颅孔 69.3%；脊神经根 95.6%。18.6%的骨骼未成熟病例采用椎体（VB）保留，且随时间推移而增加（P<0.001）。在单变量和多变量分析中，所有类别在治疗机构之间的覆盖范围均存在显著差异。筛板缺损罕见，仅眶上裂（17.4%）和额叶（12%）有轻微的边缘漏。
我们发现基于治疗机构的质子 CSI 实践存在一致的变化，包括视神经、VB、骶神经、颅神经和脊神经的覆盖范围。随着它们的不断发展，这些数据可能成为美国当前质子 CSI 实践的基准量化。
