Primary gastric cancer development after Helicobacter pylori eradication

We greatly appreciate the comment (1) on our work (2). In Japan, patients infected with Helicobacter pylori (H. pylori) undergo eradication therapy funded by the health insurance system (3). Thus, the number of gastric cancers detected after H. pylori eradication is rising. It is essential to distinguish gastric cancers detected post-eradication from cancers accompanied by current infection, because the pathophysiology of the upper gastrointestinal tract changes dramatically on H. pylori eradication (4). The risk factors for, and clinical features unique to, gastric cancer detected after eradication must be defined, and appropriate treatment strategies urgently developed.

As previously noted, we explored risk factors for primary gastric cancer that developed after H. pylori eradication in a large-scale longitudinal cohort characterized by endoscopically revealed gastric atrophy at the time of eradication. We found that the principal risk factor for gastric cancer post-eradication was advanced gastric atrophy, and that the histology of such cancers was intestinal. It has been reported that the mucosa adjacent to the cancer at the time of cancer detection was more atrophic than gastric body mucosa (5). Based on a combination of this report and our report, it is assumed that atrophic mucosa that has not fully recovered after bacterial eradication is a major risk factor for cancer development. Further work is necessary. We agree with the comment made (in another report) that endoscopic detection of gastric cancer after H. pylori eradication can sometimes be very difficult; the morphology is challenging (6). We sought to conduct endoscopy as precisely as possible. We used sufficient sedation, we employed a dye, and we vigorously biopsied small and depressed lesions in seeking to partially overcome the difficulties associated with detection. However, further studies are needed to facilitate early detection of gastric cancer after bacterial eradication. Visibility improves after eradication, sometimes allowing detection of certain lesions that were difficult to see when an H. pylori infection was present; infection is associated with mucus on the gastric mucosa, enlarged folds, and/or mucosal edema (7). Therefore, we would recommend that surveillance endoscopy be scheduled for a short period (less than 1 year, if possible) after H. pylori eradication, to ensure that missed (but significant) lesions are detected.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Laparoscopic and Endoscopic Surgery. The article did not undergo external peer review.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/ales.2017.03.20). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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