Gastric cancer molecular classification and adjuvant therapy: Is there a different benefit according to the subtype?

Background Gastric cancer (GC) has been defined in distinct molecular subtypes with different therapeutic implications. However, its clinical significance and prognosis regarding standard chemotherapy (CMT) remains unclear. This study aimed to analyze the impact of perioperative or adjuvant treatment among subtypes of GC. Methods We retrospectively evaluated all stage II/III patients with GC who underwent a curative gastrectomy. Based on immunohistochemistry and in situ hybridization techniques, GC was classified into five subtypes: Epstein‐Barr virus (EBV) positive, microsatellite instability (MSI), e‐cadherin aberrant, p53‐aberrant, and p53‐normal. Results Among the 178 CG included, 111 patients received CMT and 67 were treated with surgery alone. Survival analysis showed that p53‐aberrant GC treated with CMT had better disease‐free survival (DFS) compared with surgery alone (P = .001).There was no significant difference in DFS between patients who received CMT and those with surgery alone for EBV, MSI, E‐cadherin, and p53‐normal GC. An improvement in overall survival was observed only for E‐cadherin (P = .001) and p53‐aberrant (P