Risk factors for lymph node metastasis of submucosal invasive differentiated type gastric carcinoma: clinical significance of histological heterogeneity

Background The. use of endoscopic resection for submucosal invasive gastric carcinoma (Sm-ca) with histologically differentiated type has been expecte d. However, the treatment criteria remain controversial. The purpose of thi s study was to clarify the relationship between lymph node metastasis and t he histologic features of differentiated Sm-ca. Methods. The clinicopatholo gic features of 35 patients with node-positive differentiated Sm-ca were co mpared with those of 221 patients with node-negative differentiated Sm-ca b y multivariate: analysis with logistic regression. To clarify the metastati c behavior of differentiated Sm-ca, we examined mucin-histochemical express ion and immunohistochemical staining, using Ki-67, p53, and c-erbB2. Result s. The rate of lymph node metastasis was significantly higher in differenti ated Sm-ca with histological heterogeneity (combined differentiated type, w ith poorly differentiated component) than in that without histological hete rogeneity (27% vs 7%; P < 0.001). Multivariate analysis revealed that lymph atic vessel invasion was the most significant determinant (odds ratio, 8.68 ) for lymph node metastasis. Histological heterogeneity (odds ratio, 3.88) was next, followed by papillary adenocarcinoma (odds ratio, 3.28), and subm ucosal invasion level (odds ratio, 2.34). The mean value of the Ki-67 label ing index for node-positive differentiated Sm-ca was higher than that of no de-negative differentiated Sm-ca (47% vs 39%; P < 0.05). Conclusions. When the extension of endoscopic surgery to differentiated Sm-ca is considered, this therapeutic technique should be limited to the differentiated type of Sm-ca without histological heterogeneity. The Ki-67 labeling index provides useful information for identifying those patients with a high risk of lymp h node metastasis.