Impact of time from diagnosis to endoscopic resection on clinical outcomes in early gastric cancer

BACKGROUND: Whether a preoperative waiting period before endoscopic resection (ER) adversely affects early gastric cancer (EGC) outcomes remains unclear. This retrospective cohort evaluated whether delays up to 180 days impair oncological and pathological outcomes. METHODS: We enrolled 1646 consecutive EGC patients who underwent curative ER between 2010 and 2023. Primary endpoints were overall survival (OS) and disease-free survival (DFS); secondary endpoints included positive resection margins, pathological upstaging, curative resection rate, and additional gastrectomy requirement. Analyses comprised Kaplan-Meier curves, multivariable Cox/logistic regression with time modeled categorically (<30 vs. ≥30 days) and continuously (per 10-day increment), plus restricted cubic spline (RCS) modeling. Sensitivity analysis was conducted after excluding high risk deep submucosal (SM2) lesions. RESULTS: Median waiting time was 15 days (IQR 11-23); only 2.3% waited >90 days. Linear and RCS analyses showed no independent adverse associations between delays within 180 days and any primary or secondary endpoint (all p > 0.05). Baseline characteristics were well balanced apart from marginal discrepancies in age and family history, which were adjusted in multivariate models. Sensitivity analysis excluding SM2 lesions reproduced consistent neutral survival findings. CONCLUSION: Preoperative waiting up to 180 days was not linked to worse EGC outcomes in this cohort. These exploratory results support reasonable 6-month deferral for preoperative assessment, but marked sample‑size imbalance among long-wait patients prevents definitive validation, requiring large prospective multicenter trials.