Studies that assessed endoscopic ultrasound (index test) for evaluation of primary tumour depth of invasion (according to the American Joint Cancer Committee categories T1, T1 mucosa, T1 submucosa, T2, T3 and T4) and regional lymph node status (metastatic or disease free) against a reference standard of histopathology were eligible for inclusion. Studies needed to include at least 10 patients with histologically proven primary carcinoma of the stomach and report sufficient data to construct a 2x2 table of test performance.
Included studies were conducted in Europe, Asia and North America. The reference standard, where reported, consisted of pathology of surgical or endoscopic mucosal resection specimens. Reported definitions used to categorise T stage were uniform across studies. N stage definitions varied between studies. Endoscopic ultrasound was either radial or linear at a frequency of 5MHz to 20MHz. The stomach site of the tumour was either any or cardia.
Two reviewers independently assessed studies for inclusion; disagreements were resolved through discussion and referral to a third reviewer.