Total metabolic tumor volume by 18F-FDG PET/CT for the prediction of outcome in patients with non-small cell lung cancer

Objective Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are imaging parameters derived from 18F-FDG PET/CT that have been proposed for risk stratification of cancer patients. The aim of our study was to test whether these whole-body volumetric imaging parameters may predict outcome in patients with non-small cell lung cancer (NSCLC). Methods Sixty-five patients (45 men, 20 women; mean age ± SD, 65 ± 12 years), with histologically proven NSCLC who had undergone 18F-FDG PET/CT scan before any therapy, were included in the study. Imaging parameters including SUV max , SUV mean , total MTV (MTV TOT ) and whole-body TLG (TLG WB ) were determined. Univariate and multivariate analyses of clinical and imaging variables were performed using Cox proportional hazards regression. Survival analysis was performed using Kaplan–Meier method and log-rank tests. Results A total of 298 lesions were analyzed including 65 primary tumors, 114 metastatic lymph nodes and 119 distant metastases. MTV TOT and TLG WB could be determined in 276 lesions. Mean value of MTV TOT was 81.83 ml ± 14.63 ml (SE) whereas mean value of TLG WB was 459.88 g ± 77.02 g (SE). Univariate analysis showed that, among the variables tested, primary tumor diameter ( p = 0.0470), MTV of primary tumor ( p = 0.0299), stage ( p < 0.0001), treatment ( p < 0.0001), MTV TOT ( p = 0.0003) and TLG WB ( p = 0.0002) predicted progression-free survival in NSCLC patients, while age ( p = 0.0550), MTV of primary tumor ( p = 0.0375), stage ( p < 0.0001), treatment ( p < 0.0001), MTV TOT ( p = 0.0001) and TLG WB ( p = 0.0008) predicted overall survival. At multivariate analysis age, TLG WB and stage were retained in the model for prediction of progression-free survival ( p < 0.0001), while age, MTV TOT and stage were retained in the model for prediction of overall survival ( p < 0.0001). Survival analysis showed that patients with TLG WB ≤ 54.7 g had a significantly prolonged progression-free survival as compared to patients with TLG WB > 54.7 g ( p < 0.0001). Moreover, overall survival was significantly better in patients showing a MTV TOT ≤ 9.5 ml as compared to those having MTV TOT > 9.5 ml ( p < 0.0001). Similar results were obtained in a subgroup of 43 patients with advanced disease (stages III and IV). Conclusions Whole-body PET-based volumetric imaging parameters are able to predict outcome in NSCLC patients.