Department of Surgery, Seoul National University College of Medicine
2
Cancer Research Institute, Seoul National University Hospital
3
Department of Pathology, Seoul National University College of Medicine
Introduction: The aim of this study was to evaluate risk factors of lymph node (LN) metastasis in mucosal gastric cancer. Methods and Procedures: From 2008 to 2013, patients who underwent gastrectomy with curative intent for primary gastric adenocarcinoma with pT1a stage were retrospectively analyzed. Pathologic reports of preoperative endoscopic biopsy were compared to those of postoperative gastrectomy specimen to identify diagnostic discrepancy. Clinicopathologic characteristics were analyzed between LN negative (mLN(-))and positive (mLN(+)) groups. Ethical approval of database in this study was obtained fromInstituitional Review Board. Results: Among 1,020 patients with mucosal gastric cancer, 18 patients (1.8%) showed LN metastasis. There were no significant differences between mLN(-) and mLN(+) in terms of size of the tumor, number of retrieved LNs, venous invasion and lymphatic invasion. Proportion of LN(+) group was significantly higher in mixed-differentiated (7/139, 5.0%) adenocarcinoma patients compare to purely differentiated (1/447, 0.2%) or purely undifferentiated adenocarcinoma patients (10/434) (p<0.01). Diffuse type patients showed higher proportion of LN metastasis compared to intestinal (5/530, 0.9%) and mixed type patients (0/59, 0%)(p<0.042). Conclusion: Differentiated pT1a cancer by endoscopic biopsy may have a risk of a mixed or undifferentiated cellular component which is significantly related to LN metastasis in mucosal cancer.