Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
Int J Radiat Oncol Biol Phys. 2017 Nov 1;99(3):598-607. doi: 10.1016/j.ijrobp.2017.05.053.
Dose-volume tolerance of the spinal cord (SC) in spinal stereotactic radiosurgery (SRS) is difficult to define because radiation myelitis rates are low, and published reports document cases of myelopathy but do not account for the total number of patients treated at given dose-volume combinations who do not have myelitis. This study reports SC toxicity from single-fraction spinal SRS and presents a comprehensive atlas of the incidence of adverse events to examine dose-volume predictors.
A prospective database of all patients undergoing single-fraction spinal SRS at our institution between 2004 and 2011 was reviewed. SC toxicity was defined by clinical myelitis with accompanying magnetic resonance imaging (MRI) signal changes that were not attributable to tumor progression. Dose-volume histogram (DVH) atlases were created for these endpoints. Rates of adverse events with 95% confidence limits and probabilities that rates of adverse events were <2% and <5% for myelitis were determined as functions of dose and absolute volume.
Information about DVH and myelitis was available for 228 patients treated at 259 sites. The median follow-up time was 14.6 months (range, 0.1-138.3 months). The median prescribed dose to the planning treatment volume was 24 Gy (range, 18-24 Gy). There were 2 cases of radiation myelitis (rate r=0.7%) with accompanying MRI signal changes. Myelitis occurred in 2 patients, with Dmax >13.33 Gy, and minimum doses to the hottest 0.1, 0.2, 0.5, and 1 cc were >10.66, 10.9, and 8 Gy, respectively; however, both myelitis cases occurred below the 34th percentile for Dmax and there were 194 DVHs in total with Dmax >13.33 Gy.
A median SC Dmax of 13.85 Gy is safe and supports that a Dmax limit of 14 Gy carries a low <1% rate of myelopathy. No dose-volume thresholds or relationships between SC dose and myelitis were apparent. This is the largest study examining dosimetric data and radiation-induced myelitis in de novo spine SRS.
在脊柱立体定向放射外科（SRS）中，脊髓（SC）的剂量-体积耐受度难以确定，因为放射性脊髓炎的发生率较低，并且已发表的报告记录了脊髓病的病例，但并未说明在给定剂量-体积组合下接受治疗但没有脊髓炎的总患者人数。本研究报告了单次分割脊柱 SRS 的 SC 毒性，并提供了不良事件综合图谱，以检查剂量-体积预测因子。
回顾了 2004 年至 2011 年期间在我们机构接受单次分割脊柱 SRS 的所有患者的前瞻性数据库。SC 毒性定义为伴有磁共振成像（MRI）信号变化的临床脊髓炎，这些变化不能归因于肿瘤进展。为此端点创建了剂量-体积直方图（DVH）图谱。使用 95%置信限确定不良事件发生率，并确定脊髓炎发生率<2%和<5%的概率，作为剂量和绝对体积的函数。
在 228 名患者的 259 个部位中，提供了有关 DVH 和脊髓炎的信息。中位随访时间为 14.6 个月（范围，0.1-138.3 个月）。中位计划治疗体积的处方剂量为 24 Gy（范围，18-24 Gy）。有 2 例放射性脊髓炎（发生率 r=0.7%）伴有 MRI 信号变化。2 例脊髓炎患者的 Dmax >13.33 Gy， hottest 0.1、0.2、0.5 和 1 cc 的最小剂量分别为>10.66、10.9 和 8 Gy；然而，2 例脊髓炎病例的 Dmax 均低于第 34 百分位，总共有 194 个 Dmax>13.33 Gy 的 DVH。
中位 SC Dmax 为 13.85 Gy 是安全的，支持 Dmax 限值为 14 Gy 时脊髓病的发生率<1%。没有明显的剂量-体积阈值或 SC 剂量与脊髓炎之间的关系。这是最大的研究，检查了新发性脊柱 SRS 的剂量学数据和放射性脊髓炎。
