Abstract
In a previous population-based case-control study, we demonstrated an elevated risk of colorectal neoplasia with Helicobacter pylori (H. pylori) infection. The present study investigated the effects of H. pylori-associated chronic gastritis on the development of colorectal neoplasia by analyzing the recurrence of colorectal neoplasia subsequent to endoscopic resection. Ninety-nine patients who had undergone endoscopic resection of colorectal neoplasia were monitored under colonoscopy, and the recurrence of colorectal neoplasia was prospectively investigated. The stage of H. pylori-associated chronic gastritis in each subject was evaluated using a combination of two serum tests: H. pylori antibody and pepsinogen. In the present cohort, colorectal neoplasia recurred at a rate of 15,296/100,000 person-years during the study period. After adjusting for the confounding factors, chronic atrophic gastritis (CAG) was identified as an independent risk factor [adjusted hazard ratio (HR), 2.72; 95% confidence interval, 1.33-5.57], while H. pylori-infected non-atrophic gastritis was not identified as an independent risk factor for recurrent colorectal neoplasia. Colorectal neoplasia recurred earlier and was significantly more frequent in patients with CAG (22,573/100,000 person-years) compared to patients without CAG (11,089/100,000 person-years; P=0.029, log-rank test). Patients with more extensive CAG showed a higher risk of recurrence. These results demonstrated a significant elevation of the risk of recurrent colorectal neoplasia with the establishment and progression of CAG, indicating the involvement of H. pylori infection in the development of colorectal neoplasia. The two serum tests were useful clinical markers for noninvasively evaluating the risk of each individual for recurrent colorectal neoplasia subsequent to endoscopic resection.