Identification of patients at risk for poor survival among those with normal skeletal muscle mass: a multicenter retrospective validation study in gastric cancer

To determine the cutoff value that predicts poor long-term survival among patients without low skeletal muscle mass.

Study Design: A multicenter retrospective cohort study involving 17 hospitals in Japan, evaluating the association between preoperative skeletal muscle mass index (SMI) and clinical outcomes in gastric cancer patients undergoing radical gastrectomy.
Patient Selection: Patients diagnosed with gastric or esophagogastric junction adenocarcinoma were included, while those with low SMI, prior neoadjuvant therapy, or unsuitable conditions were excluded.
SMI Measurement: Skeletal muscle mass was assessed using preoperative CT scans, measuring the cross-sectional area of muscles at the third lumbar vertebra.
Statistical Analysis: Cox regression models were used to determine sex-specific cutoff values for SMI, and long-term survival was compared between high and r-low SMI groups.

The study identified specific cutoff values for preoperative SMI that correlate with overall survival in patients without low skeletal muscle mass.
Patients with SMI below the cutoff were categorized as having relatively low SMI (r-low SMI) within the normal range.

The study was retrospective and conducted in a single country, which may limit generalizability.
Patients with prior neoadjuvant therapy were excluded, potentially affecting the applicability of findings to a broader patient population.