Prognostic Role of Positron Emission Tomography and High-Resolution Computed Tomography in Clinical Stage IA Lung Adenocarcinoma

Background. This multicenter study aimed to validate the ability of F-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) plus high-resolution computed tomography (HR-CT) to predict the malignant behavior and prognosis of early adenocarcinomas of the lung. Methods. We calculated maximum standardized uptake values (maxSUV) from PET/CT images and ground-glass opacity (GGO) ratios on HR-CT images before complete surgical intervention in 610 patients with clinical stage IA lung adenocarcinoma. Pathologic invasiveness and survival were compared with clinical factors and radiographic findings including the maxSUV, which was revised to correct for interinstitutional discrepancies that confer limitations upon multicenter PET studies. Results. Analyses of receiver-operating characteristic curves revealed optimal maxSUV and GGO ratio cutoffs to predict recurrence of 2.9 and 25%, respectively. Both the maxSUV and GGO ratio reflected tumor invasiveness, nodal metastasis, recurrence, and patient survivals, and were significant prognostic factors for recurrence-free and cancer-specific survivals on multivariate Cox analysis (all, p < 0.001). The combination of maxSUV and GGO ratio is a better predictor of malignant tumor grade than either alone. Conclusions. The combination of maxSUV and GGO ratio as well as each alone are important predictors of prognosis in patients with clinical stage IA adenocarcinoma of the lung and should be considered before selecting therapeutic strategies. (C) 2013 by The Society of Thoracic Surgeons