Studies that investigated accuracy of endoscopic ultrasonography in differentiating between mucosal and deeper gastric carcinoma were eligible for inclusion. Only studies that used histopathological examination as the reference standard were included. Included studies were required to report sufficient data to construct 2x2 contingency tables to calculate sensitivity and specificity.
Studies that included 10 or fewer patients with gastric carcinoma, studies that only investigated gastric in a specific part of the stomach (such as gastroesophageal junction) and studies in which patients were pre-surgically treated with radiotherapy or chemotherapy were excluded.
Mean/median age of study participants, where reported, ranged from 57 to 71.5 years. The proportion of male patients ranged from 60.0% to 81.6%. Included studies were of patients with known or suspected early gastric cancer or gastric cancer. All except three of the included studies were conducted in Japan. The type and frequency of endoscopic ultrasonography transducer varied (details reported in paper).
Two reviewers independently assessed studies for inclusion. Disagreements were resolved by consensus.