Preventing Metachronous Gastric Cancer after the Endoscopic Resection of Gastric Epithelial Neoplasia: Roles of Eradication and Aspirin.

Whether eradication actually reduces the risk of metachronous gastric cancer (MGC) development remains a controversial question. In this review, we addressed this topic by reviewing the results of clinical investigations and molecular pathological analyses of the roles of eradication and aspirin administration in the prevention of MGC. In regard to the clinical studies, the results of meta-analyses and randomized control trials differ from those of retrospective studies: the former trials show that eradication has a preventive effect on MGC, while the latter studies do not. This discrepancy may be at least partly attributable to differences in the follow-up periods: eradication is more likely to prevent MGC over a long-term follow-up period (≥5 years) than over a short-term follow-up period. In addition, many studies have shown that aspirin may have an additive effect on MGC-risk reduction after eradication has been achieved. Both eradication and aspirin use induce molecular alterations in the atrophic gastritis mucosa but not in the intestinal metaplasia. Unfortunately, the molecular pathological analyses of these interventions have been limited by short follow-up periods. Therefore, a long-term prospective cohort is needed to clarify the changes in molecular events caused by these interventions.