Update on nodal staging in non-small cell lung cancer with integrated positron emission tomography/computed tomography: a meta-analysis.

Objectives: Nowadays, the number of primary studies on fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has been increasing rapidly. Thus, we updated meta-analysis to evaluate the test performance of FDG PET/CT for nodal staging in non-small cell lung cancer (NSCLC) including the most recent studies.

Methods: We performed a systematic search of MEDLINE and EMBASE for English publications using keywords "positron emission tomography", "lung cancer", and "lymph node". All searches were limited to human studies. Inclusion criteria were studies of the initial nodal staging of NSCLC with PET/CT. The reasons for exclusion are as follows: (1) studies with PET, (2) previous therapy before PET/CT, (3) nodal staging not confirmed by histology, and (4) reviews, abstracts, and editorial materials. 786 articles were identified through database searching.

Results: 28 studies including 3,255 patients and 11,887 lymph nodes (LN) were eligible for this study. The pooled sensitivity was 0.62 (95% CI 0.54-0.70), widely ranging from 0.13 to 0.98. The specificity ranged between 0.72 and 0.98 with an overall estimated specificity of 0.92 (0.88-0.95) for node-based data. The pooled sensitivity, specificity, positive and negative likelihood ratio were 0.67 (0.54-0.79), 0.87 (0.82-0.91), 5.20 (3.59-7.54), and 0.37 (0.25-0.55) for patient-based data. Studies from tuberculosis (Tb) endemic countries showed lower sensitivity (0.56 vs 0.68, p = 0.03) for node-based data and lower specificity (0.83 vs 0.89, p < 0.01) for patient-based ones.

Conclusions: PET/CT has a high specificity, but low sensitivity for detecting LN metastasis in patients with NSCLC. Tb might be one of the main reasons for lower sensitivity of PET/CT in several countries. The primary clinicians of lung cancer should be aware of the possibility of hidden metastatic LNs in bilateral FDG uptake of mediastinal and hilar LNs, especially in the Tb endemic countries.