Sarcopenia measured through body composition analysis is emerging as an important prognosticator among various malignancies, including oesophageal cancer. Skeletal muscle index (SMI) as determined by the third lumbar vertebrae on cross-sectional CT images has been demonstrated as a predictor of overall survival in oesophageal cancer, using pre-defined cut off values for sarcopenia. However, this is largely within the setting of resectable disease. The primary objective of this systematic review and meta-analysis was to determine the effect of sarcopenia defined by SMI on overall-survival in patients with unresectable oesophageal cancer. On 30 January 2021, a systematic search of the literature was conducted to identify the role of SMI among patients with unresectable oesophageal cancer, with overall survival as the primary outcome. Databases included MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library. Inclusion criteria included age >18, diagnosis of oesophageal cancer, and non-operative management. A meta-analysis was conducted using RevMan 5.4.1 using an inverse variance, random effects model. After the removal of duplicates, 2755 unique search results were obtained. Manual screening of titles and abstracts resulted in 287 full text articles that were reviewed. Of these, five studies met the inclusion criteria with data evaluating the effect of sarcopenia defined by SMI on overall survival. A total of 783 patients, the majority of which were male (n = 638, 81%), with a mean age of 68 ± 2.3 years were included. 641 (82%) patients were diagnosed with squamous cell carcinoma. Sarcopenia, as determined by SMI using pre-defined cut-off values, was reported in 517 patients (66%). Meta-analysis demonstrated decreased overall survival in the sarcopenia group compared with the non-sarcopenia group (HR = 1.51; 95% CI 1.21–1.89; P = 0.0003; I² = 0%; Figure 1). No significant publication bias was noted on assessment of funnel plot and Egger's test (P = 0.295). Sarcopenia as defined by SMI is predictive of overall survival among patients with nonoperative oesophageal cancer. Further analysis on the effect of sarcopenia on treatment related adverse effects and complications, particularly related to chemotherapy, radiotherapy, and oesophageal stenting, is needed to identify the degree of prognostication offered by body composition analysis. Studies on the modifiability of sarcopenia will help determine the utility of nutritional interventions.

中文翻译：

---

肌肉减少症会降低不可切除食管癌的总生存期：一项系统评价和荟萃分析

通过身体成分分析测量的肌肉减少症正在成为各种恶性肿瘤（包括食道癌）的重要预后因素。骨骼肌指数 (SMI) 由第三腰椎在横断面 CT 图像上确定，已被证明是食管癌总体生存的预测指标，使用预定义的肌肉减少症截止值。然而，这主要是在可切除疾病的情况下。本系统评价和荟萃分析的主要目的是确定 SMI 定义的肌肉减少症对不可切除食管癌患者总生存期的影响。2021 年 1 月 30 日，对文献进行了系统检索，以确定 SMI 在无法切除的食管癌患者中的作用，并将总生存期作为主要结果。数据库包括 MEDLINE、EMBASE、Scopus、Web of Science 和 Cochrane Library。纳入标准包括年龄>18 岁、食管癌诊断和非手术治疗。使用 RevMan 5.4.1 使用逆方差、随机效应模型进行荟萃分析。去除重复后，获得了 2755 个唯一的搜索结果。对标题和摘要进行人工筛选后，共审查了 287 篇全文文章。其中，五项研究符合纳入标准，其数据评估了 SMI 定义的肌肉减少症对总生存期的影响。共有 783 名患者，其中大多数为男性（4.1 使用逆方差、随机效应模型。去除重复后，获得了 2755 个唯一的搜索结果。对标题和摘要进行人工筛选后，共审查了 287 篇全文文章。其中，五项研究符合纳入标准，其数据评估了 SMI 定义的肌肉减少症对总生存期的影响。共有 783 名患者，其中大多数为男性（4.1 使用逆方差、随机效应模型。去除重复后，获得了 2755 个唯一的搜索结果。对标题和摘要进行人工筛选后，共审查了 287 篇全文文章。其中，五项研究符合纳入标准，其数据评估了 SMI 定义的肌肉减少症对总生存期的影响。共有 783 名患者，其中大多数为男性（n  = 638, 81%)，平均年龄为 68 ± 2.3 岁。641 (82%) 名患者被诊断为鳞状细胞癌。517 名患者 (66%) 报告了 SMI 使用预定义的截止值确定的肌肉减少症。荟萃分析表明，与非肌肉减少症组相比，肌肉减少症组的总生存率降低（HR = 1.51；95% CI 1.21–1.89；P  = 0.0003；I ²  = 0%；图 1）。在评估漏斗图和 Egger 检验时未发现明显的发表偏倚 ( P = 0.295）。SMI 定义的肌肉减少症可预测非手术性食管癌患者的总生存期。需要进一步分析肌肉减少症对治疗相关不良反应和并发症的影响，特别是与化疗、放疗和食管支架置入相关的并发症，以确定身体成分分析提供的预后程度。对肌肉减少症可改变性的研究将有助于确定营养干预的效用。