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Neoadjuvant therapy-related skeletal muscle reduction and postoperative outcomes after gastrectomy for gastric cancer: a systematic review and meta-analysis

Year: 2026

Type: article

Abstract: Background: Skeletal muscle (SM) reduction during neoadjuvant therapy (NAT) is increasingly recognized in patients with gastric cancer (GC), but its association with postoperative outcomes remains unclear. This study aimed to evaluate the association between NAT-related SM reduction and postoperative mortality, recurrence, and complications after gastrectomy for GC. Methods: This systematic review and meta-analysis was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD420261292160. MEDLINE/PubMed, Embase, Web of Science, and the Cochrane Library were searched from inception through December 15, 2025, for observational studies evaluating NAT-related muscle reduction and postoperative outcomes in GC. Muscle reduction was primarily defined by changes in the SM index (SMI) between pre- and post-NAT assessments. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects models. Results: Eleven studies were included in the systematic review, and eight contributed to the meta-analysis. NAT-related muscle reduction was associated with higher postoperative mortality at 1 year (OR 2.51, 95% CI: 1.03-6.13, P=0.04), 3 years (OR 2.67, 95% CI: 1.36-5.26, P<0.01), and 5 years (OR 1.86, 95% CI: 1.18-2.93, P=0.01). It was also associated with higher recurrence at 1 year (OR 2.00, 95% CI: 1.01-3.97, P=0.05), 3 years (OR 1.48, 95% CI: 1.03-2.12, P=0.03), and 5 years (OR 1.53, 95% CI: 1.08-2.17, P=0.02). The association with 1-year mortality was not robust in leave-one-out sensitivity analyses, whereas the 3- and 5-year mortality estimates remained stable. No clear association was observed between NAT-related muscle reduction and overall postoperative complications (OR 1.04, 95% CI: 0.66-1.63, P=0.86). Conclusions: NAT-related SM reduction was associated with increased long-term mortality and recurrence after gastrectomy for GC, but not with short-term postoperative complications. Routine assessment of dynamic body composition changes during NAT may help identify high-risk patients and guide targeted nutritional support and prehabilitation.

Source: Journal of Gastrointestinal Oncology

DOI: 10.21037/jgo-2026-0722