F-18 FDG-PET/CT parameters as predictors of outcome in non surgical NSCLC patients.
Purpose: we evaluated the prognostic significance of standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on [F-18]FDG PET/CT in patients with non-surgical non-small-cell lung cancer (NSCLC). Material and Methods: 103 patients (mean age, 65,6±16 years) underwent [F-18]FDG PET/CT before the chemotherapy. The SUVmax value, the MTV (cm3; 42% threshold) and the TLG (g) were registered. The patients were followed up 18 months thereafter (range 12-55 months). Main events such as failure to respond without progression, progression and/or disease-related death constituted surrogate end-points. The optimal SUVmax, MTV and TLG cut-off to predict the patients' outcome was estimated. PET/CT results were then related to disease outcome (progression free survival; PFS). Results: the Kaplan-Meier survival analysis for SUVmax showed a significant better PFS in patients presenting lower values as compared to those having higher (p <0.05, log-rank test). MTV and TLG were not suitable for predicting PFS apart from the subset with mediastinal nodal involvement. Conclusions: despite the availability of new tools for the quantitative assessment of disease activity on PET/CT the SUVmax rather than MTV and TLG remains the only predictor for PFS in NSCLC patients. MTV holds a value only when concomitant nodal involvement occurs.