Lymphovascular invasion is an important predictor of lymph node metastasis in endoscopically resected early gastric cancers.

With an increased incidence of early gastric cancer (EGC) and advances in endoscopic technologies, endoscopic resection (ER) has become an important treatment modality for EGC. Therefore, precise assessment of the risk of lymph node (LN) metastasis in ER specimens has become essential. The widely accepted criteria for ER have been mostly obtained from surgical data. This study was performed to evaluate the adequacy of these criteria and re-evaluate the predictive power of the criteria for LN metastasis. We evaluated a series of pathologic factors in ER specimens from 79 gastric cancer patients treated with endoscopic mucosal resection (7) or endoscopic submucosal dissection (72) and underwent subsequent surgical resection due to the potential risk of LN metastasis. Of the 79 patients, 10 patients (12.7%) exhibited regional LN metastasis. Univariate analysis revealed that the presence of lymphovascular invasion (LVI) was significantly associated with LN metastasis (26/69, 37.7 vs. 9/10, 90%, P = 0.004). The number of LVI was significantly higher in the LN metastasis group (1.1 ± 2.3 vs. 7.7 ± 8.4, P<0.001). By multivariate analysis, the presence of LVI (odds ratio, 21.41; P = 0.010) and undifferentiated histology (odds ratio, 11.15; P = 0.016) were significantly correlated with LN metastasis. The presence of LVI, undifferentiated histology and the numbers of LVI were important risk factors for LN metastasis. Among these factors, the presence of LVI was the most important risk factor for LN metastasis in endoscopically resected early gastric cancer.