Residual tumor deposits after neoadjuvant therapy and 3-year survival outcomes in gastric cancer: a single-center retrospective cohort study

The prognostic relevance of residual tumor deposits after neoadjuvant therapy (ypTD) in gastric cancer remains insufficiently defined. This study evaluated associations between ypTD positivity and 3-year disease-free survival (DFS) and overall survival (OS) after curative-intent gastrectomy. This single-center retrospective cohort study included 336 patients with locally advanced, clinically lymph node-positive gastric adenocarcinoma who underwent neoadjuvant therapy followed by R0 gastrectomy. Patients were classified by postoperative ypTD status. Survival analyses were restricted to the postoperative 36-month observation window. Kaplan–Meier analysis, log-rank tests, Cox models, exploratory ypN-stratified analyses, and within-cohort model performance comparisons were performed. Fifty-one patients (15.2%) were ypTD-positive. ypTD-positive patients had higher proportions of ypT3–4 disease, ypN2–3 disease, and lymphovascular invasion. The 3-year DFS rate was lower in the ypTD-positive group than in the ypTD-negative group (41.2% vs. 69.8%; log-rank P < 0.001), whereas 3-year OS did not differ significantly (68.6% vs. 77.9%; P = 0.063). In the fully adjusted model, ypTD positivity was associated with increased DFS event risk (HR 1.79, 95% CI 1.08–2.95; P = 0.023), but not OS (HR 0.87, 95% CI 0.46–1.65; P = 0.676). Adding ypTD increased the 36-month time-dependent AUC from 0.598 to 0.645 in within-cohort exploratory comparisons. ypTD positivity was associated with an increased risk of DFS events within 36 months after surgery, whereas no statistically significant association with OS was observed. ypTD may provide potential supplementary prognostic information for recurrence-risk assessment; however, its biological interpretation, potential clinical applicability, and long-term prognostic value require validation in larger multicenter cohorts.