Brain metastases (BM) represent the most common intracranial malignancy in adults. Limitations of existing prognostic models reduce their predictivity and clinical applicability. The aim of this study is to validate the cumulative intracranial tumour volume prognostic assessment (CITVPA) as a new prognostic score system for patients with BM treated by Stereotactic Radiosurgery (SRS). Between January 2001 and December 2015, 1894 patients underwent Gamma Knife SRS treatment. The CITVPA model was implemented and validated as follows: the CITV cut-offs were identified thanks to a receiver-operating characteristic (ROC) curve analysis; the survival predictive factors were selected through a Cox proportional hazard model; its prognostic power was compared to RPA, SIR and GPA through the Harrel concordance index (HCI). According to the ROC curve analysis, the CITV cut-off values were set at 1.5 and 4.0 cc. Based on the multivariate analysis, the CITVPA model included: age (OR 1.010, 95% CI 1.005-1.015, p < 0.001), KPS (OR 0.960, 95% CI 0.956-0.965, p < 0.001), extracranial metastases (OR 1.287, 95% CI 1.154-1.437, p < 0.001), BM number (OR 1.193, 95% CI 1.047-1.360, p = 0.008), and CITV (OR 1.028, 95% CI 1.020-1.036, p < 0.001). A score between 0 and 1 was attributed to each prognosticator; a global CITVPA score ranging from 0 to 5 was assigned with higher results corresponding to worse outcomes. The CITVPA (HCI = 0.64) exhibited a significantly (p < 0.001) higher prognostic power compared to RPA (HCI = 0.55), SIR (HCI = 0.55) and GPA (HCI = 0.61). The CITVPA represents a reliable prognostic system for patients with BM treated by SRS. However, further prospective and multicentric studies are necessary before its applicability in clinical practice.

中文翻译：

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累积颅内肿瘤体积预后评估：立体定向放射外科治疗脑转移患者的新预测评分指标。

脑转移 (BM) 是成人中最常见的颅内恶性肿瘤。现有预后模型的局限性降低了它们的预测性和临床适用性。本研究的目的是验证累积颅内肿瘤体积预后评估 (CITVPA) 作为立体定向放射外科 (SRS) 治疗的 BM 患者的新预后评分系统。2001 年 1 月至 2015 年 12 月期间，1894 名患者接受了伽玛刀 SRS 治疗。CITVPA 模型的实施和验证如下：通过接受者操作特征 (ROC) 曲线分析确定 CITV 截止值；通过 Cox 比例风险模型选择生存预测因素；通过 Harrel 一致性指数 (HCI) 将其预后能力与 RPA、SIR 和 GPA 进行了比较。根据ROC曲线分析，CITV 临界值设置为 1.5 和 4.0 cc。基于多变量分析，CITVPA 模型包括：年龄（OR 1.010，95% CI 1.005-1.015，p < 0.001），KPS（OR 0.960，95% CI 0.956-0.965，p < 0.001），颅外转移（OR 1.287 , 95% CI 1.154-1.437, p < 0.001), BM 数 (OR 1.193, 95% CI 1.047-1.360, p = 0.008), CITV (OR 1.028, 95% CI 1.020-1.036, p < 0.001)。每个预测因素的得分在 0 到 1 之间；范围从 0 到 5 的全球 CITVPA 评分被指定为较高的结果对应较差的结果。与 RPA (HCI = 0.55)、SIR (HCI = 0.55) 和 GPA (HCI = 0.61) 相比，CITVPA (HCI = 0.64) 表现出显着 (p < 0.001) 更高的预后能力。CITVPA 代表了接受 SRS 治疗的 BM 患者的可靠预后系统。然而，