Risk factors for lymph node metastasis in undifferentiated early gastric cancer

Background: Endoscopic surgery has not been accepted as a curative treatment for intramucosal undifferentiated early gastric cancer (EGC). The purpose of this study was to evaluate the predictive factors of lymph node metastasis and explore the possibility of using endoscopic surgery for undifferentiated EGC. Methods: We retrospectively analyzed 646 patients with undifferentiated EGC who had undergone gastrectomy with D2 lymphadenectomy from January 2000 to March 2005. We used univariate and multivariate analysis to identify clinicopathological features that were predictive factors for lymph node metastasis. Results: The incidence of lymph node metastasis was 4.2% in intramucosal and 15.9% in submucosal undifferentiated EGC. Multivariate analysis revealed that submucosal invasion, larger tumor size (greater than 2 cm), and presence of lymphovascular invasion (LVI), were significantly associated with lymph node metastasis in patients with undifferentiated EGC. Tumor size and LVI were independent risk factors for lymph node metastasis in cases of intramucosal EGC. Lymph node metastasis was found in only one patient (0.5%) who had neither of the two risk factors for intramucosal EGC. Conclusion: Complete endoscopic resection may be acceptable as a curative treatment for intramucosal undifferentiated EGC when the tumor size is less than or equal to 2 cm, and when LVI is absent in the postoperative histological examination. Radical gastrectomy should be recommended if LVI or unexpected submucosal invasion is present.