Objective: To investigate the prognostic value of skeletal muscle measured by CT at the level of the fourth thoracic vertebra (T4) in advanced epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients treated with ecotinib. Methods: The study retrospectively reviewed clinical and pathological characteristics of 176 patients with advanced EGFR-positive NSCLC who received ecotinib and underwent chest CT scans at Wuhan Union Hospital between January 2017 and October 2020. Among them, 70 were male and 106 were female, with ages ranging from 27 to 80 (58.6±10.6) years. As of August 21, 2021, the median follow-up duration was 19.2 months (95%CI: 15.3 to 23.7 months). The optimal cut-off value of skeletal muscle density (T4-SMD) on CT images at the T4 level were determined using X-tile software. Kaplan-Meier analysis and log-rank test were used to plot progression-free survival curves. Cox proportional hazards regression models were employed to analyze factors influencing 1-year progression-free survival (PFS), and a nomogram prognostic model was constructed accordingly. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA) were utilized to evaluate the predictive value of the nomogram. Results: The T4-SMD [M (Q1,Q3)] of 176 patients was 42.56 (37.05, 45.93) HU. Patients were divided into low T4-SMD group (n=122) and high T4-SMD group (n=54) based on the cut-off value (The values for males and females were 49.44 and 41.41 HU, respectively) of T4-SMD. The median PFS time and 1-year PFS rate in the low T4-SMD group were significantly lower than those in the high T4-SMD group [10.4 (95%CI: 9.3-11.8) vs 13.7 (95%CI: 11.1-18.5) months, 36.1% vs 59.3%, respectively, P=0.034]. Eastern Cooperative Oncology Group performance status (HR=3.308, 95%CI: 1.183-9.247, P=0.023), lactate dehydrogenase level (HR=1.852, 95%CI: 1.037-3.307, P=0.037), systemic immune-inflammation index (HR=1.772, 95%CI: 1.019-3.080, P=0.043), and T4-SMD (HR=0.563, 95%CI: 0.325-0.974, P=0.040) were prognostic factors for 1-year PFS in advanced EGFR-positive NSCLC patients treated with ecotinib. A nomogram for predicting 1-year PFS of advanced EGFR-positive NSCLC patients treated with ecotinib was constructed based on the four indicators selected by multivariate Cox regression analysis. The area under the ROC curve of the nomogram was 0.775 (95%CI: 0.676-0.874). The calibration curve showed good consistency between the predicted and actual 1-year PFS. DCA demonstrated good clinical prediction effectiveness of the nomogram. Conclusion: Low T4-SMD is a prognostic risk factor for patients with advanced EGFR-positive NSCLC receiving icotinib therapy.
目的： 探讨第4胸椎水平CT评估的骨骼肌含量对晚期表皮生长因子受体（EGFR）阳性非小细胞肺癌（NSCLC）患者埃克替尼治疗后预后的预测价值。 方法： 回顾性纳入华中科技大学同济医学院附属协和医院2017年1月至2020年10月间接受埃克替尼治疗且同时行胸部CT检查的176例晚期EGFR阳性NSCLC患者的临床资料，其中男70例，女106例；年龄27~80（58.6±10.6）岁。测量第4胸椎水平CT图像中的骨骼肌面积（T4-SMA）、骨骼肌指数（T4-SMI）、骨骼肌密度（T4-SMD）、皮下脂肪面积（T4-SAT）和皮下脂肪指数（T4-SATI）。随访截至2021年8月21日，中位随访时间为19.2（95%CI：15.3~23.7）个月。采用X-tile软件确定T4-SMD的cut-off值，Kaplan-Meier法绘制无进展生存曲线，并进行log-rank检验。使用Cox风险回归模型分析影响患者1年无进展生存率的危险因素，并据此构建列线图预测模型。采用受试者工作特征（ROC）曲线、校准曲线和决策曲线分析（DCA）评估列线图模型的预测价值。 结果： 176例患者的T4-SMD［M（Q1，Q3）］为42.56（37.05，45.93）HU，根据T4-SMD的cut-off值（男和女分别为49.44、41.41 HU）将患者分为低T4-SMD组（122例）和高T4-SMD组（54例）。低T4-SMD组中位无进展生存时间、1年无进展生存率均低于高T4-SMD组［10.4（95%CI：9.3~11.8）比13.7（95%CI：11.1~18.5）个月，36.1%比59.3%，P=0.034］。美国东部肿瘤协作组体能状态（HR=3.308，5%CI：1.183~9.247，P=0.023）、乳酸脱氢酶水平（HR=1.852，95%CI：1.037~3.307，P=0.037）、系统免疫反应指数（HR=1.772，95%CI：1.019~3.080，P=0.043）、T4-SMD（HR=0.563，95%CI：0.325~0.974，P=0.040）是埃克替尼治疗的晚期EGFR阳性NSCLC患者1年无进展生存率的影响因素。基于多因素Cox回归分析筛选的4个指标，建立用于预测埃克替尼治疗的晚期EGFR阳性NSCLC患者1年无进展生存率列线图模型的ROC曲线下面积为0.775（95%CI：0.676~0.874）。校准曲线显示，列线图模型预测的1年无进展生存率与实际无进展生存率有较高的一致性。DCA显示，列线图模型临床预测有效性较好。 结论： 低T4-SMD是接受埃克替尼治疗的晚期EGFR阳性NSCLC患者预后的危险因素。.