Muscle mass, assessed at diagnosis by L3-CT scan as a prognostic marker of clinical outcomes in patients with gastric cancer: A systematic review and meta-analysis

Computed tomographic (CT) imaging at third lumbar vertebra (L3), routinely used by oncologists, represents a reliable tool to quantify muscle mass. A systematic review and meta-analysis was performed to assess the efficacy of CT scan to define muscle mass as a prognostic marker in gastric cancer (GC) patients undergoing gastrectomy and/or chemotherapy. The primary outcomes were overall survival (OS) and recurrence-free survival (RFS) and the secondary outcomes included postoperative length of hospital stay (P-LOS), total and severe complications in GC patients undergoing gastrectomy. Three electronic bibliographic databases — MEDLINE, Web of Science and Cochrane Central Register of Controlled Trials - were used to conduct a systematic literature search based on fixed inclusion and exclusion criteria, until April 2019. The adjusted and unadjusted hazard ratio (HR), odds ratio (OR) and mean difference (MD) with 95% confidence interval (CI) were used to analyse the dichotomous variables (OS, RFS, total and severe complications) and continuous variables (P-LOS). Random- and fixed effects models were used according to the heterogeneity. A total of 5610 GC patients from 20 studies were identified. Low muscle mass at diagnosis was found in 32.7% of GC patients and was significantly associated with poorer OS (HR 2.02, 95% CI 1.71–2.38, p