Effect of preoperative oral nutritional supplements on clinical outcomes in patients undergoing surgery for gastrointestinal cancer: A systematic review and meta-analysis.

Background: The clinical benefit of preoperative oral nutritional supplements (ONS) in patients undergoing surgery for gastrointestinal cancer remains controversial.

Objective: To evaluate the effect of preoperative ONS on postoperative clinical outcomes in patients with gastrointestinal cancer.

Methods: We searched PubMed, EMBASE, Web of Science, Cochrane Library, Scopus, and the Chinese National Knowledge Infrastructure databases for randomized controlled trials evaluating preoperative ONS in patients undergoing surgery for gastrointestinal cancer from inception until April 2024.