Long-Term Surveillance After Curative Endoscopic Submucosal Dissection for Early Gastric Cancer: Distinct Clinicopathologic Characteristics of Early and Late Metachronous Neoplasia

Background: Endoscopic submucosal dissection (ESD) is an established treatment for early gastric cancer (EGC) meeting curative resection criteria. We examined clinicopathologic characteristics associated with early and late metachronous neoplasia after curative ESD. Methods: We retrospectively analyzed 185 patients who developed metachronous neoplasia among 1200 patients who underwent curative ESD for EGC. Metachronous neoplasia detected within 60 months was classified as early, and late if it is detected after 60 months. Results: Of the 185 patients with metachronous neoplasia (15.4%), 116 (62.7%) had early and 69 (37.3%) had late metachronous neoplasia; 102 developed cancer and 83 developed adenoma only. Undifferentiated histology of the index lesion was associated with late metachronous neoplasia overall (adjusted odds ratio [OR], 10.73; 95% confidence interval [CI], 1.27–90.35; p = 0.029). In the adenoma subgroup, undifferentiated histology occurred exclusively in patients with late metachronous adenoma (11.1% vs. 0%; p = 0.032), but its adjusted effect could not be estimated because of complete separation. Younger age was associated with late metachronous adenoma (adjusted OR per year, 0.937; 95% CI, 0.881–0.997; p = 0.040). In the cancer subgroup, serum triglyceride was associated with late metachronous cancer in univariable analysis (OR per 10 mg/dL, 1.064; 95% CI, 1.004–1.128; p = 0.036), but not after multivariable adjustment (p = 0.101). Conclusions: More than one-third of metachronous neoplasia were detected beyond five years after curative ESD. Undifferentiated histology was associated with late metachronous neoplasia overall and in the adenoma subgroup, although the latter association could not be adjusted. These findings warrant validation in larger cohorts.