Is endoscopic resection an alternative to surgery for early low-risk submucosal gastric cancers: analysis of a large surgical database

Background: Although endoscopic resection (ER) for early gastric cancers (EGCs) has become popular with the development of endoscopic instruments and skillful endoscopists, the risk of lymph node metastasis (LNM) is still an obstacle in performing ER. In this study, we aimed to identify the risk factors of LNM and validated the expanded criteria, with the goal of suggesting modified criteria for ER in submucosal EGCs. Methods: Of patients who underwent gastrectomy with LN dissection and were diagnosed as EGCs with depth of invasion such as sm1, sm2 or ≤500 μm from 1999 to 2008, 318 EGCs with submucosal invasion ≤500 μm were enrolled through pathologic evaluations. To identify the risk factors of LNM, a multivariate analysis of clinicopathologic factors was performed. By combining the independent risk factors of LNM, the risk of LNM was analyzed. Result: LNM were detected in 35 cases (11.0 %). Tumors >30 mm in size and with lymphatic invasion were identified as an independent risk factor for LNM in EGCs with depth of invasion ≤500 μm. Among 94 cases meeting the expanded criteria, two cases (2.1 %) were found to have LNM. Based on the submucosal invasion <300 μm, there was no LNM in EGCs with a size ≤30 mm and no lymphovascular invasion, regardless of differentiation grade. Conclusion: To exclude the possibility of LNM, applying the modified criteria based on the submucosal invasion