Expanding the Indication of Endoscopic Submucosal Dissection for Undifferentiated Early Gastric Cancer is Safe or Not?

Background: Endoscopic submucosal dissection (ESD) has gained more popularity in the treatment of early gastric cancer (EGC). Although there is a lack of confirmed evidence for the feasibility of ESD for undifferentiated EGC. The aim of the study was to investigate the feasibility of ESD with expanded indications for undifferentiated EGC patients. Methods: Data from patients with undifferentiated EGC (including signet-ring cell carcinoma, mucinous adenocarcinoma, mixed adenocarcinoma, and poorly differentiated adenocarcinoma) who underwent radical surgical resection were retrospectively reviewed. The relationship between the clinical parameters and the incidence of lymph node metastasis (LNM) was investigated. Results: A total of 517 patients were included in this study. The results showed that LNM was significantly associated with ulceration, tumor size, depth of invasion, lymphatic invasion, vascular invasion, and perineural invasion. Multivariate stepwise logistic regression analysis revealed that tumor size (OR = 1.61, 95% CI = 1.03-2.52, P = 0.0367), depth of tumor invasion (OR = 2.77, 95% CI = 1.66-4.63, P = 0.0001), and lymphatic invasion (OR = 14.74, 95% CI = 1.58-137.36, P = 0.0182) were independent risk factors for LNM. In the patients who would be included under the new proposed guidelines for ESD, including men with mucosal tumors <= 2 cm and without ulceration or lymphatic or venous infiltration, LNM was present in 11.9% (14/118). Conclusion: Caution to be exercised in expanding application of ESD should be carefully weighed in undifferentiated EGC. (C) 2019 Asian Surgical Association and Taiwan Robotic Surgery Association. Publishing services by Elsevier B.V.