In the recent years, fluorine 18 fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET)/computed tomography (CT) has emerged as a new modality for staging non-small-cell lung cancer (NSCLC) patients. The aim of this meta-analysis was to assess the diagnostic value of 18 F-FDG PET/CT in detecting metastatic lesions in NSCLC patients. Meta-analysis methods were used to pool sensitivity, specificity, positive and negative likehood ratios, diagnostic odd ratios and to construct a summary receiver-operating characteristic curve. Data from included studies were pooled to compare the diagnostic accuracy between PET/CT and PET or CT alone in nodal staging. Totally, 56 studies involving 8,699 patients met the inclusion criteria. Lung cancer is the leading cause of tumor-related deaths worldwide, and non-small-cell lung cancer (NSCLC) accounts for about 80% of all lung cancers. 1 The current criteria for staging NSCLC is based on the TNM system, 2 which determines treatment options and predicts survival. 3 So, staging NSCLC is important, and accurate clinical methods are in great need. Various diagnostic methods have been used for staging NSCLC. [4][5][6][7] Computed tomography (CT) has been widely used to evaluate the nodal status of lung cancer based on the size or shape of the lymph nodes. 8 However, the sensitivity and the specificity were relatively low, because the lymph node size may not correlate with the presence of metastatic disease. 9 Based on the fact that malignant cells show higher rates of glycolysis than most surrounding normal structures, 10 fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been introduced and developed as an effective modality for tumor staging in a variety of cancers. 11 However, PET has relatively poor spatial resolution, thus limits its anatomical localization of lesions. 12 Mediastinoscopy, endobronchial and endoscopic ultrasound, and other surgical procedures are frequently used for thoracic nodal evaluation in lung cancer, but these techniques are invasive and cumbersome. 7,13 In the past recent years, 18 F-FDG PET/CT has emerged as a new modality for staging NSCLC patients. 4,14 The aim of this study was to evaluate the diagnostic accuracy of 18 F-FDG PET/CT in detecting metastases in NSCLC patients.
Material and Methods
Selection criteriaSelection criteria were given as follows: (1) 18 F-FDG PET/CT was used for the evaluation of lymph node (LN) metastases or extrapulmonary metastases in NSCLC; (2) histologic assessment should be applied as reference standard for LN metastases; for studies evaluated extrathoracic metastases, other reference standards such as imaging modality, radiological and clinical follow-up were also applied; (3) absolute numbers of true-positive (TP), false-positive (FP), true-