Table6_Unraveling the obesity paradox in small cell lung cancer immunotherapy: unveiling prognostic insights through body composition analysis.docx

BackgroundThe advent of immunotherapy has changed the landscape of SCLC treatment, although the identification of reliable prognostic biomarkers remains a formidable challenge. Our objective was to investigate the prognostic implications of obesity and body composition in SCLC immunotherapy while seeking a straightforward anthropometric measure.
MethodsThis retrospective study analyzed data from patients with SCLC who underwent immunotherapy between 2019 and 2023. Body composition and waist circumference (WC) were analyzed using 3D slicer software on baseline CT images. Quantitative measures, including skeletal muscle index (SMI), total adipose tissue index (TATI), and other indicators at the L3 level, along with body shape index (BSI) and additional indicators based on WC, were obtained. The relationships between these indicators, response, PFS, OS, and their interconnections were examined.
ResultsA total of 145 SCLC patients who received immunotherapy were identified, of whom 133 met the inclusion criteria. In univariate analysis, a BMI≥28 kg/m2 was associated with a PFS advantage (HR 0.42, p=0.04), but this trend vanished in multivariate analysis. Body measurements exhibited stronger correlations with adipose tissue content, with BSI showing the highest correlation with muscle. In multivariate analysis, lower BSI was associated with poorer OS (HR 1.79, p=0.02). The association between muscle composition and prognosis was robust in univariate analysis but dissipated in multivariate analysis. However, accounting for a high TATI background significantly heightened the adverse effect of SMI on prognosis in the multivariate model.
ConclusionNo clear association between BMI and SCLC immunotherapy prognosis was observed. However, high adiposity exacerbated the adverse effects of sarcopenia in SCLC immunotherapy, and BSI demonstrated potential as a straightforward prognostic measure.

**背景** 免疫治疗的出现改变了小细胞肺癌（Small Cell Lung Cancer, SCLC）的治疗格局，但可靠的预后生物标志物的筛选仍是一项极具挑战性的难题。本研究旨在探讨肥胖与身体成分在小细胞肺癌免疫治疗中的预后价值，并寻求一种简便易行的人体测量指标。

**方法** 本项回顾性研究分析了2019年至2023年间接受免疫治疗的小细胞肺癌患者的临床数据。研究人员借助3D Slicer软件，对患者基线CT影像中的身体成分与腰围（Waist Circumference, WC）进行分析。获取的量化指标包括L3椎体水平的骨骼肌指数（Skeletal Muscle Index, SMI）、总脂肪组织指数（Total Adipose Tissue Index, TATI）等相关参数，以及身体形态指数（Body Shape Index, BSI）与基于腰围衍生的其他指标。随后对上述指标与治疗应答、无进展生存期（Progression-Free Survival, PFS）、总生存期（Overall Survival, OS）之间的关联及内在联系进行了分析。

**结果** 本研究共纳入145例接受免疫治疗的小细胞肺癌患者，其中133例符合入组标准。单因素分析显示，体质量指数（Body Mass Index, BMI）≥28 kg/m²与更长的无进展生存期相关（风险比（Hazard Ratio, HR）=0.42，P=0.04），但该关联在多因素分析中不再显著。人体测量指标与脂肪组织含量的相关性更强，其中身体形态指数（BSI）与骨骼肌的相关性最高。多因素分析结果表明，较低的BSI与更差的总生存期相关（HR=1.79，P=0.02）。单因素分析中，骨骼肌成分与预后的关联较为显著，但在多因素分析中该关联消失。然而，在多因素模型中纳入高TATI背景后，SMI对预后的不良影响显著增强。

**结论** 未观察到体质量指数与小细胞肺癌免疫治疗预后之间存在明确关联。但肥胖程度较高会加剧肌肉减少症对小细胞肺癌免疫治疗患者预后的不良影响，同时身体形态指数（BSI）有望成为一种简便易行的预后评估指标。