Prognostic Value of Systemic Inflammation Score for Esophageal Cancer Patients Undergoing Surgery: A Systematic Review and Meta-Analysis

Objective: The link between inflammation and cancer survival has been the subject of substantial research. The goal of this review is to summarize the evidence on the prognostic value of systemic inflammation score (SIS) in esophageal cancer patients undergoing surgical intervention. Methods: PubMed, Scopus, Embase, and Web of Science were searched for relevant articles published until 30th June 2022. We pooled adjusted data on overall survival (OS) and disease-free survival (DFS) using a random- effects meta-analysis model. The review was pre-registered on PROSPER (No. CRD42022340717). Results: Eight studies were included. All studies were conducted either in China or Japan. Six studies showed that patients with SIS of 1-2 had poor OS as compared to those with scores of 0 (HR:1.42 95% CI: 1.24, 1.62 I-2=25%). SIS of 1 (HR:1.45 95% CI: 1.18, 1.78 I-2=0%) and 2 (HR:1.94 95% CI: 1.49, 2.53 I-2=0%) were also associated with poor OS. Two studies compared the SIS score of 2 vs 0-1. Meta-analysis indicated that poor OS was associated with SIS of 2 (HR:1.80 95% CI : 1.25, 2.58). Data from three studies showed that the SIS score did not predict DFS (HR:1.40 95% CI: 0.82, 2.39 I-2=91%). Conclusion: SIS can be a novel prognostic indicator for esophageal cancer patients undergoing surgical intervention. Higher SIS is associated with a poor OS, but it does not predict DFS. Future studies are needed to strengthen the current evidence.