Predictive Value of a New Muscle Parameter in Patients with Resectable Gastric Cancer: A Pooled Analysis of Three Prospective Trials

Background Sarcopenia is closely associated with gastric cancer (GC) prognosis. However, its exact definition remains controversial. Methods This study included computed tomography images and clinical data of patients from three prospective studies. The skeletal muscle index (SMI) and skeletal muscle radiation attenuation (SMRA) were analyzed, and a new muscle parameter, skeletal muscle gauge (SMG), was obtained by multiplying the two parameters. The values of the three indices for predicting the prognosis of patients with GC were compared. Results The study included 717 patients. The findings showed median values of 42 cm 2 /m 2 (range, 36.8–48.2 cm 2 /m 2 ) for SMI, 45 HU (range, 41–49 HU) for SMRA, and 1842 (range, 1454–2260) for SMG. Postoperatively, 111 patients (15.5%) experienced complications. The 3-year overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) were 74.3%, 68.2%, and 70%, respectively. Univariate logistic analysis showed that postoperative complications were associated with SMI (odds ratio [OR] 0.94; 95% confidence interval [CI] 0.92–0.96), SMRA (OR, 0.87; 95% CI 0.84–0.90), and SMG (OR 0.99; 95% CI 0.98–0.99). After a two-step multivariate analysis, only SMG (OR 0.98, 95% CI 0.97–0.99) was an independent protective factor of postoperative complications. Multivariate analysis showed that SMG also was an independent protective factor of OS, DFS, and RFS. The patients were divided into low-SMG (L-SMG) group and high-SMG (H-SMG) groups. Chemotherapy benefit analysis of the patients with stage II low SMG showed that the OS, DFS, and RFS of the chemotherapy group were significantly better than those of the non-chemotherapy group ( p