Comparison of body composition changes and nutritional status after surgery between older Japanese patients with upper and lower gastrointestinal cancer.

Introduction: Postoperative changes in body composition and nutritional challenges are significant concerns for older patients undergoing gastrointestinal (GI) cancer surgery. This study compared body composition changes and nutritional outcomes between patients with upper gastrointestinal (UGI) and lower gastrointestinal (LGI) cancers over 12 months to identify tailored postoperative care needs.

Methods: This retrospective study included 55 Japanese patients (≥65 years) who underwent curative GI cancer surgery at the National Center for Geriatrics and Gerontology between 2018 and 2022. Patients were categorized as UGI (n = 17) or LGI (n = 38). Body composition parameters, including body mass index (BMI), fat-free mass (FFM), and body fat mass (BFM), were measured preoperatively and at 1, 3, 6, and 12 months postoperatively using bioelectrical impedance analysis. Two-way repeated-measures ANOVA was conducted, adjusting for age, sex, surgical method, operation time, blood loss, infection rates, and MMSE scores to minimize bias.

Results: UGI patients showed significant reductions in weight, BMI, FFM, and BFM postoperatively, indicating a higher risk of malnutrition and muscle loss. In contrast, LGI patients exhibited stable or increasing trends in these parameters. Significant time and interaction effects were observed for FFM and BFM (p<0.05), underscoring differential recovery patterns between groups.

Conclusions: UGI patients face a higher risk of postoperative malnutrition and muscle loss compared to LGI patients, who showed more favorable recovery trajectories. Early, intensive nutritional interventions and personalized rehabilitation strategies are essential for mitigating muscle wasting and improving outcomes in UGI patients.