Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
Int J Radiat Oncol Biol Phys. 2010 Jul 15;77(4):996-1001. doi: 10.1016/j.ijrobp.2009.06.006. Epub 2009 Sep 23.
To investigate the correlation between volume of brain irradiated by stereotactic radiosurgery (SRS) and the incidence of symptomatic and asymptomatic brain radionecrosis (RN).
A retrospective analysis was performed of patients treated with single-fraction SRS for brain metastases at our institution. Patients with at least 6-month imaging follow-up were included and diagnosed with RN according to a combination of criteria, including appearance on serial imaging and histology. Univariate and multivariate analyses were performed to determine the predictive value of multiple variables, including volume of brain receiving a specific dose (V8 Gy-V18 Gy).
Sixty-three patients were reviewed, with a total of 173 lesions. Most patients (63%) had received previous whole-brain irradiation. Mean prescribed SRS dose was 18 Gy. Symptomatic RN was observed in 10% and asymptomatic RN in 4% of lesions treated. Multivariate regression analysis showed V8 Gy-V16 Gy to be most predictive of symptomatic RN (p < 0.0001). Threshold volumes for significant rise in RN rates occurred between the 75th and 90th percentiles, with a midpoint volume of 10.45 cm(3) for V10 Gy and 7.85 cm(3) for V12 Gy.
Analysis of patient and treatment variables revealed V8 Gy-V16 Gy to be the best predictors for RN using linear accelerator-based single-fraction SRS for brain metastases. We propose that patients with V10 Gy >10.5 cm(3) or V12 Gy >7.9 cm(3) be considered for hypofractionated rather than single-fraction treatment, to minimize the risk of symptomatic RN.
研究立体定向放射外科（SRS）照射的脑体积与症状性和无症状性脑放射性坏死（RN）发生率之间的相关性。
对在我院接受单次分割 SRS 治疗脑转移瘤的患者进行了回顾性分析。纳入至少有 6 个月影像学随访的患者，并根据连续影像学和组织学表现的综合标准诊断为 RN。进行单变量和多变量分析，以确定多个变量（包括接受特定剂量的脑体积，V8 Gy-V18 Gy）的预测价值。
共回顾了 63 例患者，共 173 个病灶。大多数患者（63%）曾接受过全脑放疗。中位 SRS 处方剂量为 18 Gy。治疗的病灶中，有 10%出现症状性 RN，4%出现无症状性 RN。多变量回归分析显示，V8 Gy-V16 Gy 是症状性 RN 的最主要预测因素（p < 0.0001）。在 75%到 90%的百分位之间，出现 RN 发生率显著上升的阈值体积，V10 Gy 的中点体积为 10.45 cm3，V12 Gy 的中点体积为 7.85 cm3。
对患者和治疗变量的分析显示，在使用基于直线加速器的单次分割 SRS 治疗脑转移瘤时，V8 Gy-V16 Gy 是 RN 的最佳预测因子。我们建议将 V10 Gy >10.5 cm3 或 V12 Gy >7.9 cm3 的患者考虑进行分割治疗，以降低症状性 RN 的风险。
