Preoperative sarcopenia is a predictor of poor prognosis of esophageal cancer after esophagectomy: a comprehensive systematic review and meta-analysis

The impact of preoperative sarcopenia on long-term survival of esophageal cancer patients after esophagectomy remains unclear. We conducted an updated meta-analysis focusing on current topic comprehensively. We systematically searched relevant studies investigating the impact of preoperative sarcopenia on survival of patients with surgically treated esophageal cancer in PubMed, Embase, and Web of Science up to July 20, 2018. Data of 3-year and 5-year overall survival (OS) rates as well as hazard ratio (HR) of OS and disease-free survival (DFS) were collected for analysis by using the STATA 12.0 package. Finally, a total of 11 cohort studies consisting of 1520 patients (795 sarcopenic patients and 725 nonsarcopenic patients) were included for analysis. Our meta-analysis showed that patients with sarcopenia had a significantly lower 3-year (51.6% vs. 65.4%, P<0.001) and 5-year OS rate (41.2% vs. 52.2%, P=0.018) than those without sarcopenia. Sarcopenia was found to be an independent predictor of poor OS (HR=1.58; 95% confidence interval (CI)=[1.35, 1.85]; P<0.001) and DFS (HR=1.46; 95% CI=[1.12, 1.90]; P=0.005) in esophageal cancer patients after esophagectomy. No obvious heterogeneities or publication bias were observed during analysis. Therefore, patients with sarcopenia had a significantly worse prognosis than those without after surgical resection of esophageal cancer. Preoperative sarcopenia is an independent unfavorable prognostic factor for esophageal cancer patients after esophagectomy. However, high-quality studies with appropriate adjustments for confounding factors are needed to confirm our conclusions.