Abstract
ABC classification for gastric cancer risk to determine the requirement of further imaging test has been widely used. As an unresolved issue, however, gastric cancer sometimes occurs in Group A categorized as the lowest risk population. This issue is attributed to false negative in the test for H. pylori infection and inclusion of preexisting H. pylori infection. Serum anti-H. pylori antibody test has been developed to detect H. pylori infection; therefore there are no criteria to determine preexisting H. pylori infection. In order to determine “true” Group A population, it is critical to distinguish H. pylori infection-free cases from both preexisting and current H. pylori infection cases. Among Group A population, false negative and preexisting infection cases called false Group A population need to be excluded from Group A since they have gastric cancer risks. In this study, we examined 1,081 subjects that received health screening including gastroendoscopy as well as serum anti-H. pylori antibody test and pepsinogen test (ie, ABC screening) at our hospital in 2014. After removing 311 subjects completing H. pylori eradication before gastroendoscopy, the 770 remaining subjects were clarified into Groups A, B, C and D. There were 632 cases classified to Group A, accounting for 82.1% of total subjects. We determined “true” Group A population based on the exclusion criteria eliminating false Group A population reported by Inoue et al, ie, anti-H. pylori antibody titer of ≥3 U/mL, pepsinogen I level of ≤30 ng/mL, pepsinogen II of ≥12 ng/mL and I/II ratio of ≤4.5.“True” Group A included 480 cases (62.3%) versus 632 cases (82.1%) in the initial Group A population, and infection was endoscopically detected only in 7 subjects from “true” Group A, successfully decreasing the number of false negative Group A population to 1.1%.
