BACKGROUND AND OBJECTIVES Stereotactic radiosurgery (SRS) represents an effective treatment for pediatric arteriovenous malformations (AVMs). Biological effective dose (BED) has shown promising results in 2 previous studies as a predictive variable for outcomes in adults, but its role has never been studied in pediatric outcomes. METHODS Retrospective data for patients 18 years or younger treated with a single-session SRS for AVMs were collected from 1989 to 2019. BED calculations were performed using an α/β ratio of 2.47. Kaplan-Meier analysis was used to evaluate obliteration, new hemorrhage, and radiation-induced changes (RIC). Cox-regression analysis was used for obliteration prediction using 2 models (margin dose vs BED). RESULTS One hundred ninety-seven patients (median age = 13.1 years, IQR = 5.2) were included; 72.6% (143/197) of them presented initially with spontaneous hemorrhage. A median margin dose of 22 Gy (IQR = 4.0) with a median BED of 183.2 Gy (IQR = 70.54) was used to treat AVM with a median volume of 2.8 cm3 (IQR = 2.9). After SRS, obliteration was confirmed in 115/197 patients (58.4%) using magnetic resonance imaging and angiography at a median follow-up of 2.85 years (IQR = 2.26). The cumulative obliteration probability was 43.6% (95% CI = 36.1-50.3), 60.5% (95% CI+ = 2.2-67.4), and 66.0% (95% CI = 56.0-73.7) at 3, 5, and 10 years, respectively. In Cox multivariate analysis, a BED >180 Gy (hazard ratio [HR] = 2.11, 95% CI = 1.30-3.40, P = .002) in model 1 and a margin dose >20 Gy (HR = 1.90, 95% CI = 1.15-3.13, P = .019) in model 2 were associated with obliteration. An AVM nidus volume >4 cm3 was associated with lower obliteration rates in both models. The probability of symptomatic RIC at 10 years was 8.6% (95% CI = 3.5-13.4). Neither BED nor margin dose was associated with RIC occurrence, with the only predictive factor being deep AVM location (HR = 3, 95% CI = 1-9.1, P = .048). CONCLUSION This study confirms BED as a predictor for pediatric AVM obliteration. Optimization of BED in pediatric AVM SRS planning may improve cumulative obliteration rates.

中文翻译：

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伽玛刀放射外科治疗儿科患者动静脉畸形闭塞的生物有效剂量和预测。

背景和目标 立体定向放射外科（SRS）是治疗小儿动静脉畸形（AVM）的有效方法。生物有效剂量 (BED) 在之前的两项研究中作为成人结局的预测变量显示出有希望的结果，但其在儿科结局中的作用从未被研究过。方法 收集 1989 年至 2019 年接受单次 SRS 治疗 AVM 的 18 岁或以下患者的回顾性数据。使用 α/β 比值 2.47 进行 BED 计算。Kaplan-Meier 分析用于评估闭塞、新出血和辐射引起的变化 (RIC)。Cox 回归分析用于使用 2 个模型（边缘剂量与 BED）的闭塞预测。结果 纳入 197 名患者（中位年龄 = 13.1 岁，IQR = 5.2）；其中 72.6% (143/197) 最初表现为自发性出血。中位边缘剂量为 22 Gy (IQR = 4.0)，中位 BED 为 183.2 Gy (IQR = 70.54)，用于治疗中位体积为 2.8 cm3 (IQR = 2.9) 的 AVM。SRS 后，115/197 名患者 (58.4%) 通过磁共振成像和血管造影在中位随访 2.85 年 (IQR = 2.26) 中确认了闭塞。3 年、5 年和 10 年累积消失概率分别为 43.6% (95% CI = 36.1-50.3)、60.5% (95% CI+ = 2.2-67.4) 和 66.0% (95% CI = 56.0-73.7)。分别。在 Cox 多变量分析中，模型 1 中的 BED >180 Gy（风险比 [HR] = 2.11，95% CI = 1.30-3.40，P = 0.002），边缘剂量 >20 Gy（HR = 1.90，95% CI） = 1.15-3.13，P = .019）在模型 2 中与湮没相关。在两个模型中，AVM 病灶体积 >4 cm3 均与较低的闭塞率相关。10 年出现症状性 RIC 的概率为 8.6% (95% CI = 3.5-13.4)。BED 和边缘剂量均与 RIC 发生无关，唯一的预测因素是深部 AVM 位置（HR = 3，95% CI = 1-9.1，P = .048）。结论 这项研究证实 BED 是儿科 AVM 闭塞的预测因素。儿科 AVM SRS 计划中 BED 的优化可能会提高累积闭塞率。