Clinical significance of a papillary adenocarcinoma component in early gastric cancer: a single-center retrospective analysis of 628 surgically resected early gastric cancers

We recently reported that the presence of a papillary adenocarcinoma (pap) component was an independent risk factor for lymphatic involvement in endoscopically resected early gastric cancer (EGC). This study aimed to investigate the potential association between the presence of a pap component in EGC and lymph node metastasis (LNM). In order to evaluate the association between LNM and clinicopathological features, including a pap component, we reviewed 628 surgically resected EGCs at our institution between 2009 and 2012. Clinicopathological features included age, gender, tumor location, macroscopic type, tumor size, histological type, depth, ulcerative findings, and lymphatic and venous involvement. In addition, the association between clinicopathological features and lymphatic involvement was also evaluated. LNM was observed in 52 cases (8.3%). Univariate analyses revealed a significant correlation between a pap component and LNM as well as tumor size, depth, macroscopic type, a poorly differentiated adenocarcinoma component, and lymphatic and venous involvement. The percentage of positive LNM among the EGC cases with a pap component was significantly higher than in those without the component (18.2 vs. 7.3%, P = 0.010). Via multivariate analyses lymphatic involvement was identified as the strongest risk factor for LNM [odds ratio (OR) 14.1] and a pap component was revealed as an independent risk factor for lymphatic involvement (OR 3.1). Our study revealed that EGC cases with a pap component were at higher risk of lymphatic involvement and showed a higher percentage of positive LNM. More attention should be paid to a pap component in EGC.