Diagnostic and Predictive Values of 18F-FDG PET/CT Metabolic Parameters in EGFR-Mutated Advanced Lung Adenocarcinoma

Purpose: The clinical implications of the metabolic parameters of F-18-fluorodeoxyglucose positron emission tomography-computed tomography (F-18-FDG PET/CT) in epidermal growth factor receptor (EGFR)-mutated lung cancer are not fully understood. The aim of this study was to evaluate the diagnostic and prognostic utility of the parameters in EGFR-mutated lung cancer patients. Patients and Methods: We retrospectively enrolled 134 patients with advanced lung adenocarcinoma (72 EGFR-negative and 62 EGFR-positive). We evaluated the correlation between EGFR mutational status and the maximum standardized uptake value (SUVmax), as well as the associations between treatment outcomes in EGFR-mutated patients and various metabolic parameters of primary tumors. For the best predictive parameters, we calculated the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) using two SUV cutoffs: 1.5 (MTV1.5, TLG(1.5)) and 2.5 (MTV2.5, TLG(2.5)). Results: Mean SUVmax was lower for EGFR-mutated tumors compared with EGFR wildtype (6.11 vs 10.41, p < 0.001) tumors. Low SUVmax was significantly associated with positive EGFR mutation (odds ratio = 1.74). Multivariate analysis for survival demonstrated that high MTV1.5, TLG(1.5), MTV2.5, and TLG(2.5) were independently associated with shorter progression-free survival (PFS) and overall survival (OS), and the highest hazard ratios were found in TLG(1.5) (3.26 for PFS and 4.62 for OS). Conclusion: SUVmax may be predictive for EGFR mutational status, and MTV and TLG of primary tumors may be promising prognostic parameters; 18F-FDG PET/CT has potential utility for the risk stratification of EGFR-mutated patients treated with targeted therapy.