Abstract: Objective To retrieve, synthesize and evaluate the evidence on preoperative nutritional intervention for gastric cancer patients undergoing neoadjuvant chemotherapy (NACT), and to provide an evidence⁃based foundation for clinical practice. Methods Following the "6S" evidence resource model, systematic searches were conducted in the databases or websites including BMJ Best Practice, UpToDate, the Guidelines International Network （GIN）, Scottish Intercollegiate Guidelines Network （SIGN）, European Society for Clinical Nutrition and Metabolism (ESPEN), American Society for Parenteral and Enteral Nutrition (ASPEN), Chinese Society of Parenteral and Enteral Nutrition (CSPEN), Chinese Society of Clinical Oncology (CSCO),   PubMed, Web of Science, Ovid, Medline, Cochrane Library, JBI Library,  China Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), Wanfang Database for Chinese/English literature on nutritional management in gastric cancer NACT patients. Literature types included clinical decision⁃making, guidelines, expert consensuses, systematic reviews, Meta⁃analyses, evidence summaries, and randomized controlled trials with a search timeframe from database inception to May 2024. Two researchers independently performed literature screening and quality assessment. After consulting evidence⁃based nursing experts, evidence extraction and synthesis were conducted for qualified studies. Results A total of 20 articles were included: 2 clinical decisions, 9 guidelines, 3 expert consensuses, 4 systematic reviews, and 2 randomized controlled trials. Evidence was synthesized into 27 recommendations across 5 themes: multidisciplinary collaboration, comprehensive nutrition assessment, nutritional interventions strategies, chemotherapy gastrointestinal symptom management, nutrition education and monitoring. Conclusions This study synthesizes 27 pieces of best evidence on preoperative nutritional intervention for gastric cancer NACT patient across 5 domains, demonstrating strong practicability and scientific rigor. These findings provide actionable guidance for personalized nutritional management in clinical settings.

Key words:  Gastric cancer, Neoadjuvant chemotherapy, Nutritional intervention, Evidence?based nursing, Best evidence