IDDF2018-ABS-0127 Early gastric mucinous adenocarcinomas and signet-ring cell carcinomas did not show higher invasion capacity compared with conventional adenocarcinoma in western population

Abstract

Background Little was known about the behaviour of early gastric mucinous adenocarcinomas (MAC) and signet-ring cell carcinomas (SRC) in Western populations. The purpose of this study was to investigate whether lymph node metastasis (LNM) and survival were correlated with histology including MAC, SRC and conventional adenocarcinomas (AC) in the Western populations. Methods The Surveillance, Epidemiology, and End Results (SEER) database were used to identify all patients with surgically resected, histologically diagnosed early gastric cancer (EGC), including AC, MAC and SRC between 2004 and 2014. Logistic regression and competing risk model were used to explore whether LNM and survival differed among the above three subtypes of EGC. Results Of 2632 patients eventually included in this study, MAC and SRC accounted for 1.13% and 17.31%, respectively. Early gastric MAC or SRC patients had a numerically higher rate of LNM (28.57% and 21.34% respectively) than 18.41% for AC patients without significant difference (p=0.151). Patients with MAC and SRC demonstrated similar risk in LNM in relative to those with AC (odds ratio (OR), 1.16; 95% confidence interval (CI), 0.50–2.73, p=0.728 and OR, 1.22; 95% CI, 0.92–1.63, p=0.175, respectively) in the multivariate logistic regression. The cause-specific survival of the patients with early gastric MAC or SRC was similar as that for AC patients (p=0.0703) (figure 1). The cumulative incidence of cause-specific death was not significantly different between MAC, SRC and AC patients (p=0.1094). MAC and SRC patients tended to have similar survival as compared with AC patients (MAC: sub-distribution hazard ratio (SHR), 0.54; 95% CI. 0.13–2.22, p=0.397 and SRC: SHR, 0.87; 95% CI, 0.62–1.23, p=0.435) in the multivariate competing risk model. When MAC and SRC patients were further compared to AC patients with grade III/IV, LNM and survival were still not correlated with histology. Conclusions Early gastric MAC and SRC had similar behaviour compared with AC in Western population and histology itself is not an independent predictor of LNM and prognosis.