Abstract:

Objective: To retrospectively analyze the clinicopathological data of gastric cancer (GC) in order to investigate the histological classification and epidemiological characteristics of GC in China. Methods: A total of 3 071 cases of malignant gastric epithelial tumors who underwent surgery in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from January 2019 to July 2022 were included. The relevant pathological and clinical data were summarized and analyzed according to the 5th Edition of WHO classification of digestive system tumors and literatures was reviewed. Results: Among 3 071 cases of GC, 3 003 were diagnosed as having adenocarcinoma. The male to female incidence ratio was 2.18:1, with a median age of 64 years. It showed tubular adenocarcinoma, papillary adenocarcinoma, mixed adenocarcinoma, poorly cohesive carcinoma and mucinous adenocarcinoma are the most common. In this study, these 5 histological subtypes accounted for 96.84% of all gastric adenocarcinomas. For Lauren classification, ratio of intestinal type to diffuse type was 1.39:1. MMR deficiency was found in 5.73% of gastric adenocarcinoma cases, among which 163 cases were with loss of MLH1 and PMS2 expression. It revealed that 1.40% of the cases were positive for Epstein-Barr virus encoded small RNA (EBER). In the human epidermal growth factor receptor-2 (HER2) testing by immunohistochemistry (IHC) for adenocarcinoma, the cases of protein expression for IHC score 2+ and 3+ were 229 and 113. Conclusions: The pathological subtype distribution of gastric cancer in China has its unique characteristics, with a ratio of intestinal adenocarcinoma to diffuse adenocarcinoma lower than average level in Asian. The proportion of Epstein-Barr virus (EBV) positive gastric cancer is lower than the average level at abroad, while the proportions of cases with HER2 IHC score 2+ or 3+ are also lower than foreign reports.

Key words: Gastric carcinoma, Histopathological classification, Molecular classification