Influence of body composition on short- and long-term clinical outcomes in patients undergoing laparoscopic gastrectomy.

Gastric Cancer (GC) is the fifth most common malignancy and third leading cause of cancer-related deaths globally. Despite therapeutic advances, advanced GC prognosis remains suboptimal. Body composition (decreased muscle mass, intramuscular fat deposition, visceral obesity) has prognostic value in cancer, but the combined impact of these components on outcomes of laparoscopic gastrectomy is understudied. This retrospective cohort study included 728 GC patients who underwent laparoscopic-assisted radical gastrectomy (2018-2021). Preoperative third lumbar computed tomography (CT) quantified skeletal muscle index (SMI, indicating decreased muscle mass), skeletal muscle density (SMD, low SMD indicating intramuscular fat deposition), and visceral fat area (VFA, ≥100 cm indicating visceral obesity). Patients with decreased muscle mass, low SMD, or VFA ≥100 cm had longer stays higher costs, more complications (all P < 0.05), and worse OS (P = 0.001, P < 0.001, P = 0.039 respectively). Decreased muscle mass was an independent poor survival predictor (HR = 1.567, 95% CI:1.120-2.192, P = 0.009). All three markers correlated (P < 0.001) and exerted a cumulative adverse effect on overall survival (all positive = worst OS, P < 0.001). In conclusion, these body composition factors associate with adverse short- and long-term outcomes in GC patients post-laparoscopic gastrectomy, aiding preoperative assessment and targeted nutrition interventions.