Abstract
BACKGROUND: Metabolic syndrome (MetS) has been related to the increased incidence of esophageal cancer (EC). The aim of the study was to evaluate the influence of MetS on prognosis of patients with surgically treated EC in a systematic review and meta-analysis. METHODS: An extensive search was conducted on PubMed, Embase, Web of Science, Wanfang, and CNKI to identify relevant cohort studies. Random-effects models were employed to combine the findings, taking into account the potential influence of heterogeneity. RESULTS: Seven cohort studies involving 4332 patients with stage I-III EC who received surgical resection were included. At baseline, 608 (14.0%) patients had MetS. Pooled results suggested that MetS were associated with a higher risk of postoperative complications (risk ratio [RR]: 1.30, 95% confidence interval [CI]: 1.03 to 1.64, p = 0.03; I(2) = 0%). However, the overall survival (RR: 1.07, 95% CI: 0.75 to 1.52, p = 0.71; I(2) = 80%) and progression-free survival (RR: 1.27, 95% CI: 0.53 to 3.00, p = 0.59; I(2) = 80%) were not significantly different between patients with and without MetS. Subgroup analyses suggested that the results were not significantly modified by study design (prospective or retrospective), histological type of EC (squamous cell carcinoma or adenocarcinoma), or diagnostic criteria for MetS (p values indicating subgroup difference all > 0.05). CONCLUSION: Although MetS may be associated with a moderately increased risk of postoperative complications in patients with EC under surgical resection, the long-term survival may not be different between patients with and without MetS.