Risk Factors for Lymph Node Metastasis in Undifferentiated Early Gastric Cancer

The indication for endoscopic resection is differentiated gastric cancer ≤ 2 cm in size without an ulcer, of which the depth of invasion is clinically diagnosed as tumor confined to the mucosa. Endoscopic resection is not indicated for undifferentiated gastric intramucosal carcinoma, which is associated with a high rate of lymph node metastasis. This study aimed to analyze the factors associated with lymph node metastasis and to determine the validity of endoscopic resection in patients with undifferentiated early gastric cancer (EGC). This study included 141 patients who underwent gastrectomy with lymph node dissection for undifferentiated EGC. The clinicopathological findings were retrospectively analyzed to identify the factors associated with lymph node metastasis. According to the depth of tumor invasion, lymph node metastasis was observed in 13 patients (9.2%), including three with intramucosal carcinoma (3.6%) and ten with submucosal invasive carcinoma (17.2%). Univariate analysis identified tumor size (p = 0.038), depth of tumor invasion (p = 0.008), and lymphovascular invasion (LVI) (p = 0.0002) as risk factors for lymph node metastasis. On multivariate analysis, LVI (p = 0.002) was identified as the only independent risk factor for lymph node metastasis. The use of endoscopic resection for the undifferentiated EGC should be considered carefully for patients with LVI because of the risk for lymph node metastasis.