Factors influencing occurrence of metachronous gastric cancer after endoscopic resection: a systematic review and meta-analysis

Background/Aims: Metachronous gastric cancer (MGC) can occur after endoscopic resection for gastric cancer. Further studies on factors other than Helicobacter pylori infection are needed. This systematic review and meta-analysis aimed to evaluate risk factors for metachronous recurrence of endoscopically resected gastric cancer. Methods: We searched medical literature published by February 2023 and identified patients with MGC after endoscopic resection for gastric cancer. The occurrence of MGC and the presence of intestinal metaplasia (IM), severe atrophic gastritis (AG), and H. pylori infection were quantitatively analyzed. Results: We identified 2,755 patients from nine cohort studies who underwent endoscopic resection for gastric cancer by 2018. Those with severe AG or presence of IM had a significantly higher incidence of MGC than those without (RR 2.00, 95% CI 1.35–2.98, I² = 52% for severe atrophy on antrum; RR 7.08, 95% CI 3.63–13.80, I² = 0% for antral IM). Absolute risk difference of MGC occurrence was 7.1% in those with severe AG and 9.2% in those with IM. The difference in incidence rate per 1,000 person-years was 17.5 person-years for those with severe AG and 24.7 person-years for those with IM. How-ever, H. pylori eradication did not significantly affect the occurrence of MGC (RR 1.18, 95% CI 0.88–1.59, I² = 10%). Conclusions: Gastric cancer patients with severe AG or presence of IM had a 2.0-fold or 7.0-fold higher risk of MGC occurrence after endoscopic resection than those without, respectively. They need more stringent follow-up to monitor MGC occurrences (CRD42023410940).