Imaging in assessing lymph node status in gastric cancer

Accurate assessment of lymph node status is of crucial importance for appropriate treatment planning and determining prognosis in patients with gastric cancer. The aim of this study was to systematically review the current role of imaging in assessing lymph node (LN) status in gastric cancer. A systematic literature search was performed in the PubMed/MEDLINE and Embase databases. The methodological quality and diagnostic performance of the included studies was assessed. Six abdominal ultrasonography (AUS) studies, 30 endoscopic ultrasonography (EUS) studies, 10 multidetectorrow computed tomography (MDCT) studies, 3 conventional magnetic resonance imaging (MRI) studies, 4 F-18-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) studies, and 1 FDG-PET/CT fusion study were included. In general, the included studies had moderate methodological quality. The sensitivity and specificity of AUS varied between 12.2% and 80.0% (median, 39.9%) and 56.3% and 100% (median, 81.8%). The sensitivity and specificity of EUS varied between 16.7% and 95.3% (median, 70.8%) and 48.4% and 100% (median, 84.6%). The sensitivity and specificity of MDCT varied between 62.5% and 91.9% (median, 80.0%) and 50.0% and 87.9% (median, 77.8%). The sensitivity and specificity of MRI varied between 54.6% and 85.3% (median, 68.8%) and 50.0% and 100% (median, 75.0%). The sensitivity and specificity of FDG-PET varied between 33.3% and 64.6% (median, 34.3%) and 85.7% and 97.0% (median, 93.2%). The sensitivity and specificity of the FDG-PET/CT fusion study were 54.7% and 92.2%. For all the imaging modalities, there were no significant differences between the mean sensitivities and specificities of high- and low-quality studies. AUS, EUS, MDCT, conventional MRI, and FDG-PET cannot reliably be used to confirm or exclude the presence of LN metastasis. The performance of highresolution PET/CT fusion and functional MRI techniques still has to be determined.