AIM To assess whether extent of surrounding edema correlates with acute adverse clinical outcomes within 3 months after stereotactic radiosurgery (SRS) for melanoma brain metastases (BM). METHODS Patients with melanoma BM treated with SRS were included in a single center retrospective analysis. A contrast-enhanced magnetic resonance image (MRI) brain was acquired on the day of treatment and used to calculate the volume of the largest lesion (the index BM) and total volume of all BM. Their corresponding volume of surrounding edema was defined based on the fluid attenuated inversion recovery (FLAIR) sequence. After SRS, MRI was performed every 3 months for at least 2 years if the patient remained well enough to do so. Adverse neurologic events after SRS were defined using common terminology criteria for adverse events (CTCAE) version 5.0. Multivariate regression analyses assessed for associations between BM size and edema at baseline with increasing edema and neurologic adverse events within 3 months after SRS. RESULTS Mean volume of the index BM reduced from 2.2 to 0.5 cm3 at 3 months after SRS (p = 0.03). Mean volume of edema surrounding the index BM was 6.4 cm3 at baseline, 10.2 cm3 at 3 months and 5.5 cm3 at 6 months. There were 7/43 (16%) patients that experienced an adverse neurological event within 3 months (attributable to any cause) and 4/43 (9%) were associated with an increase in BM edema. On univariate and multivariate analyses, there were no correlations between any baseline factors and volume of edema at 3 months. However, SRS dose delivered and systemic therapy use within 4 weeks of SRS both correlated with a reduction in edema surrounding the index BM. CONCLUSION A transient increase in mean volume of edema was apparent at 3 months after SRS. However, this resolved by 6 months and did not correlate with adverse events or dexamethasone requirement. Thus, the clinical significance is uncertain.

中文翻译：

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黑色素瘤脑转移放疗后周围水肿的程度与急性并发症无关。

目的评估在黑色素瘤脑转移瘤（BM）的立体定向放射外科手术（SRS）后3个月内周围水肿的程度是否与急性不良临床结果相关。方法采用单中心回顾性分析纳入接受SRS治疗的黑色素瘤BM患者。在治疗当天获取对比增强磁共振图像（MRI）的大脑，用于计算最大病变的体积（指数BM）和所有BM的总体积。根据液体衰减反转恢复（FLAIR）序列定义其相应的周围水肿体积。SRS后，如果患者状况良好，则每3个月进行MRI检查至少2年。使用常见的不良事件术语标准（CTCAE）5.0版定义了SRS后的不良神经事件。多变量回归分析评估了基线时BM大小与水肿与SRS后3个月内水肿增加和神经系统不良事件之间的相关性。结果SRS后3个月，BM指数的平均体积从2.2 cm3降低至0.5 cm3（p = 0.03）。基线周围BM的平均水肿体积在基线为6.4 cm3，在3个月时为10.2 cm3，在6个月时为5.5 cm3。在3个月内有7/43（16％）的患者发生神经系统不良事件（归因于任何原因），而4/43（9％）的患者则与BM水肿增加有关。单因素和多因素分析显示，3个月时任何基线因素与水肿量之间均无相关性。但是，在SRS的4周内递送的SRS剂量和全身治疗均与BM周围水肿的减轻相关。结论SRS后3个月，平均水肿体积出现短暂性增加。但是，这可以在6个月内解决，并且与不良事件或地塞米松的需求量无关。因此，临床意义尚不确定。