Abstract
BACKGROUND: The objective of this study was to investigate the prognostic significance of parameters derived from ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging in patients with advanced non-small cell lung cancer (NSCLC) receiving first-line treatment with immune checkpoint inhibitors (ICIs) and platinum-based chemotherapy, focusing on both primary tumors and metastatic sites located in the torso. METHODS: This retrospective study analyzed 70 patients diagnosed with stage III or IV NSCLC who underwent FDG PET/computed tomography (CT) prior to initiating first-line treatment with ICI-based combination therapy. Key metabolic metrics-including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)-were quantified across all detectable lesions within the torso. Associations between these PET-derived parameters and clinical outcomes, including progression-free survival (PFS) and overall survival (OS), were examined using Kaplan-Meier survival estimates and Cox proportional hazards regression. RESULTS: MTV-torso and TLG-torso were significantly higher in patients with poor Eastern Cooperative Oncology Group performance status (PS ≥ 2). In univariate analyses, PS, MTV-torso, and TLG-torso were significantly associated with both PFS and OS. In multivariate analyses, PS and MTV-torso remained independent predictors of both outcomes. Patients with lower MTV-torso (< 225.81) had significantly higher mean PFS (582.3 vs. 154.5 days, P < 0.001) and OS (1,047.6 vs. 291.4 days, P < 0.001). SUVmax-torso was not significantly associated with survival. CONCLUSIONS: Among the FDG PET-based volumetric indices, MTV-torso emerged as an independent predictor of both PFS and OS in patients with advanced NSCLC undergoing first-line treatment with ICI and platinum-based chemotherapy. These findings support the use of torso-based metabolic tumor burden assessment as a valuable tool for prognostic stratification in this patient population.