Characteristics of gastric cancer in negative test of serum anti-Helicobacter pylori antibody and pepsinogen test: a multicenter study

Background and aim The serological risk prediction system combines the pepsinogen test and anti-Helicobacter pylori (H. pylori) antibody determination. In this system, chronic atrophic gastritis (CAG) is diagnosed using the pepsinogen test. Patients who are H. pylori negative and pepsinogen negative are classified into group A, are assumed to be H. pylori uninfected, and are at an extremely low risk for gastric cancer. However, gastric cancers are detected in this group. The aim of this study is to clarify the clinicopathological status of group A patients with gastric cancer. Methods A total of 109 gastric cancer patients classified as group A were enrolled in a multicenter study. Group A patients were divided into two subgroups: group AN (H. pylori uninfected) and group AP (H. pylori infected). They were compared to 183 H. pylori-infected gastric cancer patients who were not in group A. Results Of the 109 patients, only 7 were classified as group AN; the other 102 were classified as group AP. The clinicopathological features of group AP included older age, predominantly differentiated type cancer, endoscopically visualized CAG, and pepsinogen (PG) I/II ratio lower than that of group AN. In group AN, the depressed type was dominant, and the PG I/II ratio was higher than in those gastric cancer patients who were infected with H. pylori. Conclusion Patients in group AP had CAG, and their gastric cancers were similar to those of H. pylori-eradicated patients. Concerning the recent ABC classification system, advanced decision criteria should be proposed to decrease the false-negative evaluation of gastric cancer risk.