Diagnostic Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Preoperative Mediastinal/Extramediastinal Nodal Staging of Non–Small-Cell Lung Carcinoma

Introduction: Lung cancer has the highest incidence and mortality among malignancies in many countries. 18 F-Fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) is commonly indicated for the preoperative nodal staging of non–small-cell lung carcinoma. While maximum standardised uptake value (SUV max ), visual scoring systems and nodal diameter have been proposed to distinguish benign from malignant nodes, studies comparing the different measurements have been limited. Correct nodal staging is crucial in determining if treatment intent is curative or palliative. This study aimed to evaluate the accuracies of nodal staging in 18 F-FDG PET/CT based on different methods. Methods: A total of 467 mediastinal/extramediastinal lymph nodes from 97 patients, who underwent staging 18 F-FDG PET/CT at our centre for non–small-cell lung carcinoma, were retrospectively reviewed. The nodes were evaluated based on SUV max , five-point visual interpretation score, and diameter. Their sensitivities, specificities and accuracies were compared with histology using receiver operating characteristics curves and areas under the curves (AUCs). Subgroup analyses based on T staging, histology, epidermal growth factor receptor (EGFR) status, lymph node locations, and tumour SUV max were also investigated. Results: The diagnostic performance of visual score (at optimal cut-off of 3) yielded the highest specificity (0.932), accuracy (0.916), positive predictive value (0.623), and negative predictive value (0.972), results of which were similar to SUV max of 2.5 and better than nodal diameter of 10 mm. Subgroup analyses showed that visual interpretation achieved satisfactory AUCs in different T stages, histologies, EGFR statuses, locations of lymph nodes, and tumour SUVs max . Conclusion: The five-point visual interpretation is a convenient diagnostic tool with performance better than nodal diameter, and similar to that of SUV max .