Computed tomography defined body composition may predict postoperative outcomes and prognosis following gastric cancer surgery.

Objective: Loss of muscle mass (sarcopenia) and impaired muscle quality (myosteatosis) associated with poor surgical outcomes. This study aimed to evaluate the impact of sarcopenia and myosteatosis on postoperative short-term outcomes and prognosis in patients with gastric cancer.

Material and methods: Patients who underwent gastric cancer surgery and had abdominal computed tomography (CT) imaging were included in the study. Skeletal muscle index (SMI) and skeletal muscle density (SMD) were calculated using CT images. Patients were divided into groups based on previously established threshold values: Those with low SMI (indicating sarcopenia) versus those with normal SMI, and those with low SMD (indicating myosteatosis) versus those with normal SMD. Demographics, clinicopathologic characteristics, postoperative outcomes, and survival data were extracted from prospective database.

Results: Among the 237 patients, 87 patients (36.7%) had sarcopenia and 139 patients (58.6%) had myosteatosis. Patients with myosteatosis were characterized by older age, poorer preoperative nutritional status, inferior performance status, and extended hospital stays. Higher severe complication incidence was observed among patients with myosteatosis (18% vs. 10.2%, p=0.09). Overall survival of patients with sarcopenia or myosteatosis was significantly lower than that of patients with a normal SMI or SMD (p=0.03, p<0.001 respectively). Myosteatosis was identified as an independent risk factor for overall survival in multivariate analysis (hazard ratio: 2.20, 95% confidence interval: 1.26-3.86, p=0.006).

Conclusion: This study indicated sarcopenia or myosteatosis is associated with reduced overall survival. Although there were no significant difference severe complication rates are higher in patients with low SMD than in patients with normal SMD, and reporting of SMD from preoperative CT should be considered in preoperative evaluation.