Prognostic Analysis of Gastric Signet Ring Cell Carcinoma and Hepatoid Adenocarcinoma of the Stomach: A Propensity Score-Matched Study

BACKGROUND: Hepatoid adenocarcinoma of the stomach (HAS) is a rare type of primary gastric cancer, and most previous studies have reported that HAS has a poor prognosis due to its aggressive biological behavior. The aim of this study was to compare the prognosis of HAS to that of gastric signet ring cell carcinoma (SRC). METHODS: This was a single-center, retrospective, observational cohort study (January 2010 to January 2016) of gastric cancer patients with pathological HAS and SRC. Overall survival was compared between HAS and SRC patients. We used univariate Cox regression, multivariate Cox regression, propensity score matching (PSM), inverse probability of treatment weighting, standardized mortality ratio weighting, standardized mortality ratio weighting, and overlap weighting to perform a prognostic analysis. RESULTS: A total of 725 (672 SRC and 53 HAS) patients were included. After nearest-neighbor 1:4 PSM, 200 SRC patients and 50 HAS patients were matched. Only in univariate Cox regression analysis with the cohort before PSM did HAS show a significantly worse prognosis than SRC [hazard ratio (HR), 1.66; 95% confidence interval (CI), 1.02–2.69, p = 0.040]. However, in the analysis of multivariate Cox regression with the cohort before PSM and series analysis based on the propensity score, all of the results indicated that there was no statistically significant difference in overall survival between HAS and SRC (all p > 0.05). Furthermore, in the subgroup of proximal location (p = 0.027), T stage 4a & 4b (p = 0.001), N stage 3a & 3b (p = 0.022), with cancer nodules (p = 0.026), serum CEA higher than the normal value (p = 0.038), and serum CA199 higher than the normal value (p = 0.023), the prognosis of HAS was significantly worse than that of SRC. CONCLUSION: Based on our study, there was no statistically significant difference in overall survival between HAS and gastric SRC patients. However, in patients with an advanced tumor stage, HAS may have a worse overall survival than SRC.