Efficacy and safety of neoadjuvant ICI-based regimens in resectable gastric and GEJ cancer: Updated systematic review and meta-analysis.

Abstract

e16124 Background: Gastric and gastroesophageal junction (GEJ) cancers remain highly lethal, and durable cure relies on curative resection and deep pathologic response. Despite neoadjuvant chemotherapy, relapse is frequent. With newly published, more mature studies reporting resection, downstaging, and perioperative safety for neoadjuvant immune checkpoint inhibitor (ICI) based therapy, we updated prior limited syntheses to refine contemporary efficacy and toxicity estimates. Methods: We performed a PRISMA-compliant systematic review and meta-analysis of studies comparing neoadjuvant ICI-based therapy versus non-ICI regimens in resectable gastric/GEJ cancer, using the most mature reports. Outcomes were overall survival (HR), resection rate, pCR, ypT-0, ypT-1, ypT-2 downstaging, any-grade adverse events, and grade 3–4 adverse events (all pooled as ORs) with random-effects models and I² heterogeneity. Results: We performed a PRISMA-compliant systematic review and meta-analysis of studies comparing neoadjuvant ICI-based therapy versus non-ICI regimens in resectable gastric/GEJ cancer, using the most mature reports. Outcomes were overall survival (HR), resection rate, pCR, ypT-0, ypT-1, ypT-2 downstaging, any-grade adverse events, and grade 3–4 adverse events (all pooled as ORs) with random-effects models and I² heterogeneity. Conclusions: Neoadjuvant ICI-based therapy improved resection and pathological response without clear excess toxicity, but OS benefit was not demonstrated. Prospective trials and standardized reporting are needed to determine whether pathological gains translate into durable survival.