Abstract
The ABC classification helps in the stratification of patients with gastric cancer into the high-risk group and creates an opportunity for such patients to undergo endoscopic examination, thereby contributing to the improvement of gastric cancer detection rate. However, cancers that cannot be ignored are still included in Group A, which results in an extremely low incidence of cancer. The reason for this issue could be a false group A, which is known to harbor current and previous H. pylori infections. Therefore, knowledge regarding the exclusion of false group A is important; however, as a countermeasure, we included subjects who had the following data into group Aʹ: Hp antibody, 3-9.9 U/mL; PG I, <30 ng/mL; PG II, >12 ng/mL; or PG I/II, 4.5 ng/mL, as measured using the Eiken Chemical E plate. Since the introduction of the ABC classification in the 2016 fiscal year in Oamishirasato City, group Aʹ was established as a countermeasure against false A group. Endoscopic atrophy was observed in 49.4% of the endoscopic findings of subjects in groupAʹ (237 cases) who appeared to have a current or a previous infection. However, the remaining 50.6% of cases were false-positive, and this proportion should be reduced in the future. After the introduction of the ABC classification, the cancer detection rate increased from 0.19% to 0.34%, compared with the rate when gastric cancer was screened by MDL. Eight patients had gastric cancer (1 patient in group B, 5 patients in group C, 2 patients in group D, and none in group Aʹ); however, the rate of atrophy was 49.4%, and there was a risk of gastric cancer. The introduction of the ABC classification as a countermeasure against a false group A appears to be useful because of the increase in the detection rate of cancer.
