Role of PET/CT in Management of Early Lung Adenocarcinoma.

OBJECTIVE. The purpose of this study was to explore the value of FDG PET combined with high-resolution CT (HRCT) in predicting the pathologic subtypes and growth patterns of early lung adenocarcinoma. MATERIALS AND METHODS. A retrospective analysis was conducted on the PET/CT data on ground-glass nodules (GGNs) resected from patients with stage IA lung adenocarcinoma. The efficacy of PET maximum standardized uptake value (SUVmax) combined with HRCT signs in prediction of histopathologic subtype and growth pattern of lung adeno-carcinoma was evaluated. RESULTS. SUVmax was significantly higher in GGNs with invasive HRCT signs. The diameter of GGN (odds ratio, 1.660; p = 0.000) and the difference in attenuation value (odds ratio, 1.012; p = 0.011) between ground-glass components and adjacent lung tissues were independent predictors of FDG uptake by GGNs. SUVmax was higher in invasive adenocarcinoma than in adenocarcinoma in situ (AIS)-minimally invasive adenocarcinoma (MIA) (median SUVmax, 2.0 vs 1.1; p = 0.008). An SUVmax of 2.0 was the optimal cutoff value for differentiating invasive adenocarcinoma from AIS-MIA. Acinar-papillary adenocarcinoma had a higher SUVmax than lepidic adenocarcinoma (median SUVmax, 2.1 vs 1.3; p = 0.037). An SUVmax of 1.4 was the optimal cutoff value for differentiating the growth pattern of adenocarcinoma. Use of PET/CT with HRCT significantly improved efficacy for differentiating invasive adeno-carcinoma from AIS-MIA. However, use of HRCT cannot significantly improve the diagnostic efficacy of FDG PET in the evaluation of tumors with different growth patterns. CONCLUSION. FDG PET can be used to predict the histopathologic subtypes and growth patterns of early lung adenocarcinoma. Combined with HRCT, it has value for predicting invasive histopathologic subtypes but no significance for predicting invasive growth patterns.