Mapping the Evidence on Neoadjuvant Response and Gastrectomy Extent in Gastric Cancer: A Scoping Review

Neoadjuvant therapy improves R۰ resection and survival in locally advanced gastric and gastroesophageal junction adenocarcinoma, but the extent to which treatment response should modify surgical strategy remains uncertain. Response is most commonly assessed using tumor regression grade (TRG) and pathological complete response (pCR), whereas radiological, endoscopic, biomarker-based, and nodal response assessments are less consistently integrated into surgical planning.This scoping review aimed to map the evidence on how response to neoadjuvant therapy is assessed and how it may influence surgical planning and the extent of gastric resection. The review followed Joanna Briggs Institute methodology and PRISMA-ScR. PubMed, Scopus, Embase and Google Scholar were searched from inception. Studies involving adults with gastric or gastroesophageal junction adenocarcinoma treated with neoadjuvant therapy followed by surgery were considered. Data were charted regarding response assessment, surgical strategy, resection margins, lymphadenectomy, reconstruction, and clinical modifiers.The search identified ۱,۴۳۵ records; after screening and full-text assessment, ۱۳ evidence sources were included. Pathological response was dominant, with TRG and pCR consistently associated with prognosis. A meta-analysis of ۱۱ studies and ۲,۷۳۳ patients reported that lower TRG was associated with improved DFS (HR ۰.۵۳) and OS (HR ۰.۵۹). In an NCDB analysis of ۷,۲۵۸ patients, pCR occurred in ۹.۳% and was associated with longer median OS (۱۶۷.۹ vs ۶۵.۸ months; P<۰.۰۰۱). Direct evidence linking response to gastrectomy extent was concentrated in proximal gastric cancer, where propensity-score-matched studies showed comparable OS, PFS, and complications between proximal gastrectomy (PG) and total gastrectomy (TG), with PG showing advantages in reflux (۱۸.۰% vs ۳۱.۱%; P=۰.۰۱۷) and operative time. Tumor size ≤۴ cm, histological differentiation, and nodal response were key modifiers.Treatment response has strong prognostic relevance, but its translation into surgical decision-making remains incompletely established. Current direct evidence is strongest for selected proximal gastric cancers in which favorable response may permit PG rather than TG. However, evidence supporting response-guided subtotal, pylorus-preserving, local, sentinel-node-based, or other organ-preserving surgery remains limited or indirect. Resection margins and nodal response remain critical constraints. Prospective trials integrating multimodal response assessment are required before routine response-guided surgical de-escalation can be recommended.

کلیدواژه ها:

gastric cancer ، neoadjuvant therapy ، treatment response ، gastrectomy