This is the protocol for a review and there is no abstract. The objectives are as follows:
To provide readers with both a comprehensive overview and a quantitative analysis of the published data regarding the ability of EUS to preoperatively define the locoregional disease spread (i.e., primary tumor depth [T-stage] and regional lymph node status [N-stage]) in patients with primary gastric carcinoma.
To provide readers with the tools to calculate EUS diagnostic accuracy measures based on pre-test information, such as gastric cancer T-stage and N-stage prevalence (Bayes nomograms).
In order to investigate the potential sources of heterogeneity, we will use subgroup analysis and meta-regression to assess the effect of various factors on the diagnostic accuracy of EUS, such as year of publication, country (Western versus Eastern), EUS technical features (radial versus linear array; ultrasound frequency [MHz]), definition of target condition (for N-stage: lymph node morphology versus size), gastric tumor site (any site versus cardia only) and prevalence of target condition.