Synchronous and Metachronous Multiple Gastric Epithelial Neoplasms Detected During Index Evaluation and Post‐Endoscopic Submucosal Dissection Surveillance: A Descriptive Comparison

Abstract

ABSTRACT Objectives We compared synchronous and metachronous gastric tumors detected during index evaluation and surveillance after endoscopic submucosal dissection (ESD), focusing on Kimura‐Takemoto O‐3 atrophy. Helicobacter pylori eradication history and the neutrophil‐to‐lymphocyte ratio (NLR) were exploratory. Methods We retrospectively reviewed consecutive patients who underwent ESD. Patients whose first additional lesion was detected simultaneously or within 1 year after index ESD were classified as having synchronous gastric tumors (SGT); those with no synchronous lesion whose first additional lesion was detected later were classified as having metachronous gastric tumors (MGT). Logistic regression estimated associations with SGT rather than MGT presentation. Results Among 1064 screened patients, 256 had multiple lesions (SGT, n = 169; MGT, n = 87). SGT patients were older (median, 76 vs. 72 years; p = 0.005), and O‐3 atrophy was more frequent (34.3% vs. 20.5%; p = 0.045). In exploratory multivariable analysis, age (adjusted odds ratio [aOR], 1.67 per 10 years; 95% confidence interval [CI], 1.12–2.51) and O‐3 atrophy (aOR, 2.17; 95% CI, 1.01–4.65) were associated with SGT presentation. Eradication timing was unavailable, and NLR was not independently associated with SGT. Conclusions O‐3 atrophy was more frequent when the first additional lesion was detected synchronously. SGT and MGT may represent timing‐defined phenotypes within a continuous atrophic field rather than biologically distinct entities. Extensive atrophy supports meticulous whole‐stomach inspection at index evaluation and sustained surveillance.