Purpose

Since frameless stereotactic radiosurgery (SRS) techniques have been recently introduced, hypofractionated SRS (HF-SRS) for large brain metastases (BMs) is gradually increasing. To verify the efficacy and safety of HF-SRS for large BMs, we aimed to perform a systematic review and compared them with SF-SRS.

Methods

We systematically searched the studies regarding SF-SRS or HF-SRS for large (> 2 cm) BM from databases including PubMed, Embase, and the Cochrane Library on July 31, 2018. Biologically effective dose with the α/β ratio of 10 (BED₁₀), 1-year local control (LC), and radiation necrosis (RN) were compared between the two groups, with the studies being weighted by the sample size.

Results

The 15 studies with 1049 BMs that described 1-year LC and RN were included. HF-SRS tended to be performed in larger tumors; however, higher mean BED₁₀ (50.1 Gy₁₀ versus 40.4 Gy₁₀, p < 0.0001) was delivered in the HF-SRS group, which led to significantly improved 1-year LC (81.6 versus 69.0%, p < 0.0001) and 1-year overall survival (55.1 versus 47.2%, p < 0.0001) in the HF-SRS group compared to the SF-SRS group. In contrast, the incidence of radiation toxicity was significantly decreased in the HF-SRS group compared to the SF-SRS group (8.0 versus 15.6%, p < 0.0001).

Conclusion

HF-SRS results in better LC of large BMs while simultaneously reducing RN compared to SF-SRS. Thus, HF-SRS should be considered a priority for SF-SRS in patients with large BMs who are not suitable to undergo surgical resection.

中文翻译：

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大（> 2 cm）脑转移瘤的单次和大分割立体定向放射外科：系统评价

目的

由于最近引入了无框架立体定向放射外科 (SRS) 技术，用于大脑转移瘤 (BM) 的大分割 SRS (HF-SRS) 正在逐渐增加。为了验证 HF-SRS 对大型 BM 的疗效和安全性，我们旨在进行系统评价并将其与 SF-SRS 进行比较。

方法

我们于 2018 年 7 月 31 日从 PubMed、Embase 和 Cochrane Library 等数据库中系统检索了关于 SF-SRS 或 HF-SRS 对大（> 2 cm）BM 的研究。生物有效剂量，α/β 比为 10（ BED ₁₀ )、1 年局部对照 (LC) 和放射性坏死 (RN) 在两组之间进行比较，研究按样本量加权。

结果

包括描述 1 年 LC 和 RN 的 1049 个 BM 的 15 项研究。HF-SRS 倾向于在较大的肿瘤中进行；然而，HF-SRS 组的平均 BED ₁₀更高（50.1 Gy ₁₀对 40.4 Gy ₁₀，p  < 0.0001），这导致 1 年 LC 显着改善（81.6 对 69.0%，p  < 0.0001）和 1- 与 SF-SRS 组相比，HF-SRS 组的年总生存率（55.1% vs 47.2%，p < 0.0001）。相比之下，与 SF-SRS 组相比，HF-SRS 组的辐射毒性发生率显着降低（8.0 对 15.6%，p  < 0.0001）。

结论

与 SF-SRS 相比，HF-SRS 导致大型 BM 的 LC 更好，同时降低了 RN。因此，对于不适合手术切除的大 BM 患者，HF-SRS 应优先考虑 SF-SRS。