Prognostic role of preoperative skeletal muscle mass index in surgical lung cancer patients: a systematic review with meta-analysis.

BACKGROUND: The prognostic value of preoperative skeletal muscle mass index (SMI) in lung cancer patients who undergo the surgery remains unclear. This meta-analysis aimed to clarify prognostic value of preoperative SMI with long-term survival among operated lung cancer patients. METHODS: PubMed, Cochrane Library, and Web of Science databases were searched up to March 21, 2026. Endpoints for survival included the overall survival (OS), disease-free survival (DFS) and cancer-specific survival (CSS). Subgroup analyses stratified by the neoadjuvant therapy and tumor type for OS were further performed. RESULTS: Fourteen retrospective studies with 8,008 participants were included. After combining available data, it was identified that a lower SMI was associated with poorer OS [hazard ratio (HR) =1.35, 95% confidence interval (CI): 1.30-1.52, P<0.001] and DFS (HR =2.10, 95% CI: 1.06-4.15, P=0.03) and potentially poorer CSS (HR =1.64, 95% CI: 0.91-2.95, P=0.10). Subgroup analyses for the OS based on the neoadjuvant therapy (no: HR =1.90, P=0.003; yes: HR =2.50, P=0.03; mixed: HR =1.27, P=0.004) and tumor type (non-small cell lung cancer: HR =1.28, P<0.001; lung cancer: HR =2.03, P<0.001) manifested consistent results. CONCLUSIONS: Lower preoperative SMI was associated with worse survival among surgical lung cancer patients and may have potential value in prognostic assessment.