Bioelectrical impedance-derived body composition and systemic therapy outcomes in non-small cell lung cancer

Body mass index (BMI) cannot distinguish skeletal muscle from adipose tissue or capture fat distribution in non-small cell lung cancer (NSCLC). We explored whether bioelectrical impedance analysis (BIA)-assessed body composition was associated with systemic therapy outcomes.

Consecutive adults with confirmed NSCLC who underwent pretreatment multifrequency BIA between March 2023 and March 2025 were retrospectively included. Analyses were performed by treatment context, including stage I surgical patients and stage II-IV patients receiving immune checkpoint inhibitor (ICI)- or epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI)-based systemic therapy. Body-composition parameters were compared by clinical stage and EGFR mutation status using analysis of covariance (ANCOVA). Progression-free survival (PFS) was analyzed using Kaplan-Meier methods and Cox proportional hazards models. Objective response rate (ORR) was evaluated using logistic regression. Joint analyses were performed according to skeletal muscle index (SMI) and visceral fat index (VFI), and longitudinal body-composition changes during immunotherapy were also assessed.

Among 473 screened patients, 369 were included, comprising 126 with stage I disease and 243 with stage II-IV disease. After predefined exclusions, outcome cohorts included 125 ICI-treated and 43 EGFR-TKI-treated patients. In cross-sectional analyses, adiposity-related parameters were nominally lower in stage II-IV disease than in stage I disease, but these differences did not remain significant after false discovery rate (FDR) correction; no body-composition parameter differed significantly by EGFR mutation status. Among 94 men included in the primary ICI PFS analysis, high SMI was associated with longer PFS [adjusted hazard ratio (HR), 0.49; 95% confidence interval (CI): 0.25-0.97], whereas high VFI was associated with shorter PFS (adjusted HR, 2.11; 95% CI: 1.09-4.07). High SMI was also associated with higher ORR among these men [adjusted odds ratio (OR), 3.04; 95% CI: 1.20-7.72]. The combined SMI/VFI phenotype further stratified PFS, with low SMI/high VFI identifying the least favorable subgroup. In an exploratory longitudinal analysis, a >10% decrease in trunk fat mass was associated with shorter PFS. No clear associations between body-composition parameters and PFS were observed in the small EGFR-TKI cohort.

BIA-assessed skeletal muscle reserve and visceral adiposity were associated with outcomes during ICI-based therapy in men with NSCLC. Higher SMI and lower VFI identified a more favorable clinical profile. Prospective validation is warranted to define the role of BIA-based body-composition assessment in host-related risk stratification during systemic therapy.