Prognostic significance of preoperative skeletal muscle status in patients with gastric cancer after radical gastrectomy

Background and Objectives: The association between skeletal muscle status and gastric cancer (GC) prognosis remains unclear. Here, we investigated the impact of the skeletal muscle index (SMI) on overall survival (OS) in GC patients after radical gastrectomy. Methods and Study Design: We divided 178 patients into four groups: adult men, adult women, elderly men and elderly women. The SMI, calculated using CT images, of patients was graded using cutoff values of group-specific tertiles. Age, body mass index, SMI grade, Charlson comorbidity index, surgical method (total vs distal gastrectomy), tumor stage, and histological type and differentiation were included in Cox regression models to assess the primary outcome parameter of OS. A new prognostic score for 3-year OS was established by combining the SMI grade and tumor stage, and receiver operating characteristic (ROC) curve analyses were used to determine its predictive reliability. Results: For groups with high, medium, and low SMI grades, the 3-year OS rates were 94.04, 79.08 and 59.09% and 86.09, 70.11 and 49.11% (p<0.001) in patients undergoing distal and total gastrectomy, respectively. In the multivariate analysis, low SMI (hazard ratio (HR) 1.82, 95% confidence interval (CI) 1.14-2.9), advanced stage (HR 2.89, 95% CI 1.43-5.83), and total gastrectomy (HR 1.69, 95% CI 0.95-3.01) were independent risk factors for OS (p<0.010). The areas under the ROC curves for the prognostic score were 0.77 (range 0.61-0.93) and 0.76 (range 0.65-0.86) in patients undergoing distal and total gastrectomy, respectively. Conclusions: The preoperative SMI was an independent prognostic factor for long-term survival in GC patients after radical gastrectomy.