Endoscopic Submucosal Dissection (ESD) is considered the standard treatment for early gastric neoplastic lesions according to Japanese and ESGE guidelines. However, evidence from Western populations remains limited. This study reports the interim results of a single and high-volume Western referral center from a prospective multicenter national registry endorsed by the SIED, evaluating ESD efficacy, safety, and the diagnostic accuracy of biopsies pre-ESD in a real-world Western cohort.

We analyzed 105 consecutive patients who underwent gastric ESD between January 2021 and June 2025 at a tertiary referral center. Demographics, lesion characteristics, procedural outcomes, adverse events, and follow-up findings were assessed. Primary endpoints were en bloc, R0 and curative resection rates, and procedure-related adverse events. Secondary endpoints included recurrence, metachronous lesions, predictors of treatment failure, and diagnostic accuracy of biopsies pre-ESD.

En bloc resection were achieved in 92.4%, R0 resection in 90.5%, and curative resection in 85.7% of cases, respectively. Procedure-related perforation and delayed bleeding occurred in 4.8% of cases each. Median procedure time was 60 minutes and median hospital stay was 3 days. No local recurrence was observed during follow-up, while metachronous lesions occurred in 9.5% of patients. Lesions located in the cardia were significantly associated with lower en bloc resection rates (p = 0.0013). Concordance between pre-ESD biopsy and final ESD histology was limited (κ = 0.24), with a biopsy sensitivity of 50% and specificity of 96.9% for early gastric cancer.

In this large Western prospective cohort, ESD demonstrated high efficacy and a favorable safety profile, fully comparable to the outcomes from Asian referral centers. The absence of local recurrence confirms its oncological reliability. The high rate of biopsy underdiagnosis underscores the importance of ESD for accurate staging and definitive treatment, particularly for lesions that appear to exhibit low or intermediate dysplasia. These results support the broader adoption of ESD in Western clinical practice in the future.