Clinical outcome of non-curative endoscopic submucosal dissection for early gastric cancer.

Background: Early gastric cancer (EGC) is defined as cancer cells confined to the mucosal or submucosal layer, irrespective of size or presence of lymph node metastasis. The recent EGC endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) guidelines (2021 Japan Gastroenterological Endoscopy Society (JGES) guidelines, 2nd edition) revised the concept from "endoscopic curative/non-curative resection" (NCR) to "endoscopic curability (eCura)". Under this, eCuraA and eCuraB signify curative resections (CRs), while eCuraC (including eCuraC-1 and eCura-C2) indicate NCRs. This study retrospectively analyzes clinical and pathological data from EGC patients who underwent endoscopic resection, assessing the long-term clinical outcomes in a substantial cohort after undergoing NCR. Methods: We retrospectively analyzed clinical and pathological data from 443 EGC patients, encompassing 478 lesions, who received endoscopic treatment. The long-term clinical outcomes of patients who underwent NCR were statistically evaluated. Characteristics of the NCR group were compared with those of the surgical group, employing single- and multi-factor logistic regression analyses to identify risk factors that necessitate further surgical intervention. Prognostically, the Kaplan-Meier method and Log-Rank test determined the impact of risk factors on recurrence-free survival post-surgery in NCR patients. Differences were assessed using a method incorporating statistically significant differences in the multi-factor Cox regression analysis, evaluating the hazard ratio (HR) for disease recurrence following NCR. Results: In this study, 443 EGC cases were pathologically diagnosed, comprising a total of 478 lesions. Of these, 127 cases underwent non-curative endoscopic resection, resulting in a NCR rate of 24.4%. Long-term follow-up was achieved for 117 (92.12%) patients. The metastasis/recurrence rate at 6 months stood at 23.1%. Multivariate Cox regression analysis identified lesion size ≥2.0 and <3 cm [P=0.02, HR =0.12, 95% confidence interval (CI): 0.02-0.67], presence of ulceration (P=0.03, HR =5.48, 95% CI: 1.23-24.33), lymphatic invasion (P=0.05, HR =17.51, 95% CI: 1.07-286.23), positive vertical margins (P=0.09, HR =3.77, 95% CI: 0.81-17.53), and flat macroscopic morphology (P=0.048, HR =4.8, 95% CI: 1.01-22.73) as independent risk factors for recurrence-free survival post non-curative endoscopic resection in EGC patients. Conclusions: The recurrence/metastasis rate in patients who underwent NCR is notably higher compared to the control group. Significant prognostic risk factors include tumor size ≥2.0 and <3 cm, positive vertical margins, lymphatic invasion, and flat type (one of pathological gross classification). Patients in the eCuraC-2 category of NCR should consider further surgical intervention. The necessity for additional surgical intervention in these patients warrants further investigation.