Background:The cachexia index (CXI) has been proposed as a novel biomarker of cancer cachexia. We aimed to investigate the association between CXI and survival outcomes after stereotactic radiotherapy (SRT) in patients with non-small cell lung cancer (NSCLC) and brain metastases.Methods:Data from 145 patients with NSCLC, who underwent SRT for brain metastases between April 2016 and August 2020, were retrospectively analyzed. Cachexia index was calculated as skeletal muscle index (SMI) × serum albumin level/neutrophil-to-lymphocyte ratio, whereas SMI was calculated from computed tomography images captured at the L1 level. Kaplan-Meier curves and Cox proportional hazards models were used to assess progression-free survival (PFS) and overall survival (OS). The prognostic values of CXI and other cachexia biomarkers were assessed using receiver operating characteristic (ROC) curve analysis.Results:Lower pretreatment CXI (<30.8) was significantly associated with older age ( P = .039), lower Karnofsky performance score ( P = .009), and a high likelihood of extracranial metastases ( P = .001). Patients with a lower pretreatment CXI had a significantly shorter PFS and OS than those with a higher CXI ( P < .001). Multivariate analysis revealed that pretreatment CXI was an independent risk factor for both PFS, hazard ratio (HR) = 2.375; 95% confidence interval (CI) = 1.610-3.504; P < .001, and OS, HR = 2.340; 95% CI = 1.562-3.505; P < .001. Compared with other biomarkers, pretreatment CXI had the highest area under the ROC curve value for prognostic assessment, reaching 0.734. Moreover, the loss of CXI was a strong risk factor for survival independent of pretreatment CXI ( P = .011).Conclusions:Cachexia index may serve as a clinically useful tool for predicting survival outcomes of patients with NSCLC and brain metastases who undergo SRT.

中文翻译：

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非小细胞肺癌合并脑转移瘤患者立体定向放射治疗后恶病质指数的预后意义

背景：恶病质指数（CXI）已被提议作为癌症恶病质的新型生物标志物。我们的目的是调查 CXI 与非小细胞肺癌 (NSCLC) 脑转移患者立体定向放射治疗 (SRT) 后生存结果之间的关联。方法：数据来自 145 名 NSCLC 患者，这些患者在 4 月份期间因脑转移接受了 SRT对2016年和2020年8月进行了回顾性分析。恶病质指数计算为骨骼肌指数 (SMI) × 血清白蛋白水平/中性粒细胞与淋巴细胞比率，而 SMI 是根据 L1 水平捕获的计算机断层扫描图像计算的。Kaplan-Meier 曲线和 Cox 比例风险模型用于评估无进展生存期 (PFS) 和总生存期 (OS)。使用受试者工作特征 (ROC) 曲线分析评估 CXI 和其他恶病质生物标志物的预后价值。结果：治疗前 CXI 较低 (<30.8) 与年龄较大 ( P = .039)、卡诺夫斯基表现评分较低 ( P = .009），颅外转移的可能性很高（P = .001）。治疗前 CXI 较低的患者的 PFS 和 OS 明显短于 CXI 较高的患者 ( P < .001)。多变量分析显示，治疗前CXI是两者PFS的独立危险因素，风险比（HR）= 2.375；95%置信区间（CI）=1.610-3.504；P < .001，OS、HR = 2.340；95% CI = 1.562-3.505；P < .001。与其他生物标志物相比，治疗前CXI用于预后评估的ROC曲线下面积值最高，达到0.734。此外，CXI 的丧失是独立于治疗前 CXI 的生存的强大危险因素 ( P = .011)。结论：恶病质指数可以作为预测接受 SRT 的 NSCLC 和脑转移患者的生存结果的临床有用工具。