Endoscopic ultrasonography is valuable for identifying early gastric cancers meeting expanded-indication criteria for endoscopic submucosal dissection

Endoscopic ultrasonography (EUS) has become a reliable method for predicting the invasion depth of early gastric cancer (EGC). This study evaluated the accuracy of EUS in identifying lesions meeting expanded-indication criteria for endoscopic submucosal dissection (ESD) and analyzed clinicopathologic factors influencing the diagnostic accuracy of EUS in assessing tumor invasion depth. This study investigated 542 EGCs of 515 patients who underwent EUS pretreatment. The pretreatment EUS-determined diagnosis was compared with the final histopathologic evaluation of resected specimens, and the impact of various clinicopathologic parameters on diagnostic accuracy was analyzed. The diagnostic accuracy of EUS in identifying lesions meeting expanded-indication criteria for ESD was 87.8% (259/295) for differentiated adenocarcinoma (D-type) 30 mm in diameter or smaller, 43.5% (10/23) for D-type tumor larger than 30 mm in diameter, and 75% (42/56) for undifferentiated adenocarcinoma (UD-type) 20 mm in diameter or smaller. Using multivariate analysis, the diagnostic accuracy of EUS in predicting tumor invasion depth was determined to be decreased significantly by ulcerous change and large tumor size (diameter, a parts per thousand yen30 mm). For patients with EGC, D-type lesions 30 mm in diameter or smaller and UD-type lesions 20 mm in diameter or smaller can be diagnosed with high accuracy by EUS, but larger D-type lesions (diameter, > 30 mm) should be considered carefully in terms of EUS-based treatment decisions. Findings of ulceration and large tumors are associated with incorrect diagnosis of tumor invasion depth by EUS.