Prognostic value of extracapsular invasion and fibrotic focus in single lymph node metastasis of gastric cancer

BACKGROUND: Histological findings of metastatic lymph nodes are important prognosticators in patients with gastric cancer. The aim of this study was to clarify the clinical significance of various pathological characteristics of the early phase of lymph node metastasis in patients with gastric cancer, by selecting patients with tumors that had single lymph node metastases, no serosal invasion, and no metastases to the peritoneum, liver, or distant organs. METHODS: Seventy-eight patients were eligible and were entered in this study. These patients were subdivided according to the following histological characteristics of the one metastatic lymph node: size of the metastasis (i.e., amount of tumor cells [AT]), proliferating pattern (PP), intranodal location (IL), and the presence or absence of extracapsular invasion (ECI) and/or fibrotic focus (FF). Associations between clinicopathological factors, survival, and the nodal findings were examined. RESULTS: There were no correlations between AT or PP and any clinicopathological factors. IL was significantly correlated with venous invasion and the pathological characteristics of the primary tumor. ECI and FF were observed significantly more frequently in pT2 than in pT1 cancer. Overall survival (OS) differed significantly according to depth of invasion, venous invasion, and the presence or absence of ECI or FF, although OS was not affected by AT, PP, or IL. The 10-year overall survival rates of patients with and without ECI were 50% and 80%, respectively, while these rates for patients with and without FF were 50% and 79%, respectively. Multivariate analysis revealed that ECI and FF were significant prognosticators of survival. CONCLUSION: These results strongly suggested that the presence of ECI or FF could affect the survival of patients with gastric cancer.