Sarcopenia Determined by Skeletal Muscle Index Predicts Overall Survival, Disease-free Survival, and Postoperative Complications in Resectable Esophageal Cancer A Systematic Review and Meta-analysis

Background: Sarcopenia has been identified as a prognostic factor among certain types of cancer. In esophageal cancer, patients are at increased risk of malnutrition and sarcopenia, ultimately contributing to poor outcomes. A systematic review was conducted to determine whether sarcopenia, defined by the skeletal muscle index, is predictive of overall survival, disease-free survival, and postoperative complications in resectable esophageal cancer. Materials and Methods: A systematic search of MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines up until January 2021. The primary outcome was overall survival; secondary outcomes included disease-free survival, pulmonary complications, and anastomotic leak. Results: Twenty-one studies (4 prospective; 17 retrospective; 3966 patients) were included. Sarcopenia was present in 1940 (48.1%) patients and was associated with lower overall survival [hazard ratio (HR): 1.56; 95% confidence interval (CI): 1.25-1.95; PI (2)=71%] and disease-free survival (HR: 1.73; 95% CI: 1.04-2.87; P=0.03; I (2)=51%). A decrease in skeletal muscle index, independent of sarcopenia status, was associated with lower overall survival (HR: 1.81; 95% CI: 1.20-2.73; P=0.005; I (2)=92%). Sarcopenia was associated with increased odds of pulmonary complications (odds ratio: 1.86; 95% CI: 1.29-2.66; P=0.0008; I (2)=41%) and increased odds of anastomotic leak (odds ratio: 1.46; 95% CI: 1.11-1.93; P=0.008; I (2)=0%). Conclusions: Sarcopenia is a predictor of overall survival, disease-free survival, and postoperative complications in patients with resectable esophageal cancer. Studies on the modifiability of sarcopenia in the preoperative period will help determine the utility of nutritional interventions.