Distinct Chemopreventive Effects of Aspirin in Diffuse and Intestinal-Type Gastric Cancer.

Introduction: Although aspirin/NSAIDs may have potential preventive effects on several cancers, it remains unclear on gastric cancer. The purpose of this study is to compare the risk of developing gastric cancer and the histologic changes of intestinal metaplasia and neutrophil infiltration, between aspirin/NSAID users and nonusers. Methods: Using an electronic endoscopy database in two hospitals from 1996 to 2017, we analyzed the data from patients with chronic gastritis who received aspirin or NSAIDs prior to upper gastrointestinal endoscopy. One-to-one propensity score matching was performed to compare the proportion of gastric cancer, intestinal metaplasia, and neutrophil infiltration between these drug users and nonusers. Results: We analyzed 2,082 aspirin users and 2,082 nonusers as well as 898 NSAID users and 898 nonusers. Six diffuse-type and 19 intestinal-type gastric cancer, 1,243 intestinal metaplasia, and 1,503 neutrophil infiltration patients were identified. The proportion of diffuse-type gastric cancer (0.05%) was 80% lower in aspirin users compared with the nonusers (0.24%), and there was no case of diffuse-type cancer in patients who took aspirin for more than 2 years. In contrast, intestinal-type gastric cancer incidence was significantly higher in aspirin users (0.72%) compared with nonusers (0.14%). No significant differences in the incidence of gastric cancer were found between NSAID use and nonusers. NSAID use was significantly associated with decreased proportion of neutrophil infiltration compared with nonusers. Conclusion: Aspirin may have distinct effects between intestinal-type and diffuse-type gastric cancer development. Cancer Prev Res; 11(5); 279-86. ©2018 AACR .