Endoscopic resection for mucosal gastric cancer (MGC) is highly recommended in the absence of lymph node metastasis (LNM). We aimed to clarify the risk factors for LNM in MGC and to investigate the association of LNM with the indication criteria for endoscopic submucosal dissection (ESD).
A retrospective cohort study was performed on 3,951 MGC patients who underwent radical gastrectomy at the Samsung Medical Center in Seoul, Republic of Korea between September 1994 and September 2010.
Of the MGC patients, 101 patients (2.60%) were positive for LNM. Multivariate analysis, followed by univariate analysis, revealed the following risk factors for LNM in MGC: large tumor size, undifferentiated tumor type, lymphatic invasion, perineural invasion, and associated ulceration in the tumor (HR 1.25, 7.49, 20.65, 23.45, and 4.07, respectively). Patients without LNM had significantly increased survival/recurrence-free survival rates than patients with LNM (188.4/209.8 months vs. 169.5/188.0 months; P=0.029/0.004, respectively). Only 3 (0.3%) out of 1065 patients who met the absolute indication criteria for ESD had LNM. Of those who met the expanded indication criteria for ESD, 11 (0.4%) out of 2678 patients had LNM. LNM was also found in two patients who had a differentiated tumor <0.5cm without ulceration.
The risk for LNM was very low when MGC patients met the absolute/expanded criteria for endoscopic resection, which meant the indication criteria for ESD was safe and acceptable. However, although the risk for LNM is very low, it should not be considered negligible in endoscopic resection.