Clinical Impact of the Extent of Lymph Node Micrometastasis in Undifferentiated-Type Early Gastric Cancer

Objective: Lymph node (LN) metastasis is one of the most important prognostic factors for undifferentiated-type early gastric cancer (EGC). The aim of this study was to examine expansion of micrometastasis in regional LNs to clarify the importance of lymphadenectomy for undifferentiated-type EGC. Methods: Clinicopathological features of 307 patients with undifferentiated-type EGC who underwent gastrectomy with lymphadenectomy between 1997 and 2010 at the Department of Surgical Oncology, Osaka City University, were retrospectively reviewed. Micrometastasis in LNs was detected by immunohistochemistry using anticytokeratin antibody. Results: The incidence of LN metastasis was 1.8% in patients with mucosal (pT1a) tumors and 17.3% in those with submucosal (pT1b) tumors. Multivariate analysis revealed that lymphatic invasion and tumor depth were independently related to LN metastasis. Micrometastasis was found in 41 (13.3%) patients. Twenty-two patients with pN0 had micrometastasis in the perigastric region. Micrometastasis had spread to the area along the left gastric or common hepatic artery in 12 patients. Patients with an upgraded stage by micrometastasis had significantly worse disease-free survival. Conclusions: LN micrometastasis was observed beyond the perigastric LNs and correlated with poor outcomes in patients with undifferentiated-type EGC. These data underscore the importance of adequate lymphadenectomy for patients with undifferentiated-type EGC. (C) 2014 S. Karger AG, Basel