Impact of endoscopy intervals on metachronous gastric cancer after endoscopic submucosal dissection: Comparison between 1 year and half‐a‐year

Japanese guidelines recommend posttreatment endoscopy once or twice a year after endoscopic submucosal dissection (ESD) for early gastric cancer. However, the impact of endoscopy intervals on metachronous gastric cancer (MGC) remains unclear, especially the difference between 1-year and half-a-year intervals. We aimed to investigate this difference.This study retrospectively investigated 2429 patients who underwent gastric ESD between May 2001 and June 2019 at our hospital. Patients who developed MGC were classified based on those who underwent the previous endoscopy within at least 7 months (short-interval group) and within 8-13 months (regular-interval group). Propensity score matching (PSM) was used to adjust for possible confounders. The primary outcome was the proportion of MGC beyond curative ESD criteria established in the guidelines.A total of 216 eligible patients developed MGC. The short- and regular-interval groups included 43 and 173 patients, respectively. Overall, no patients in the short-interval group had MGC beyond curative ESD criteria, while 27 patients in the regular-interval group did. The proportion of MGC beyond curative ESD criteria was significantly lower in the short-interval group than in the regular-interval group before (P = 0.003) and after (P = 0.028) PSM. Although not significant, the short-interval group tended to have a higher stomach preservation rate than the regular-interval group (P = 0.093).Our study indicated a possible benefit of biannual surveillance endoscopy in the early post-ESD period.