A pilot study of mobile application–based exercise and nutrition interventions for gastrointestinal cancer patients with low muscle mass during chemotherapy.

827 Background: Sarcopenia is linked to poor prognosis in gastrointestinal (GI) cancer patients receiving chemotherapy. This pilot study evaluated a mobile application–based exercise program combined with protein-rich oral nutritional supplements (ONS) to address sarcopenia. Methods: Patients with GI cancer receiving combination chemotherapy were screened for sarcopenia, defined as skeletal muscle index (SMI) T-score < –1 (skeletal muscle area at L3/body mass index, BMI) on routine abdomen–pelvis CT, using artificial intelligence software (AID-UTM, iAID Inc., Seoul, Korea). Participants received a mobile app–guided, multicomponent exercise program (MyVivache, DYPHI Inc., Daejeon, Korea) tailored to Short Physical Performance Battery (SPPB) scores (<6, 7–9, ≥10), 5 days/week for 12 weeks, plus daily soybean-based ONS (190 kcal, 26 g protein/day). Assessments at baseline, 6, and 12 weeks included CT-derived SMI, bioelectrical impedance analysis (BIA), SPPB, handgrip strength, Mini Nutritional Assessment–Short Form (MNA-SF), and quality of life (EORTC-QLQ-C30). Results: Between April 2024 and June 2025, 29 patients were enrolled; as of July 30, 2025, 23 completed 12 weeks of intervention, 3 remain ongoing, and 3 withdrew. Median age was 61 years (range 39–72); 48% were male. Cancer sites included colorectal (22), pancreatic (4), small bowel (1), ampulla of Vater (1), and appendix (1). Three (10%) had locally advanced and 26 (90%) metastatic disease. The mean compliance was 73% for exercise and 75% for ONS. EORTC-QLQ-C30 showed no major changes except improved constipation at 12 weeks. Handgrip strength and MNA-SF were unchanged. Conclusions: A mobile application–based exercise program combined with ONS during chemotherapy was feasible in GI cancer patients with sarcopenia, showed stable muscle mass during 12 weeks of intervention, and modest improvements in physical performance. Outcome Baseline (mean ± SD) 6 weeks 12 weeks SMI T-score (CT) –1.84 ± 0.52 –1.84 ± 0.58 –1.89 ± 0.62 SPPB score 11.14 ± 1.13 11.70 ± 0.73* 11.67 ± 1.24* Skeletal muscle mass (kg) (BIA) 22.6 ± 5.51 23.09 ± 5.61 22.56 ± 5.39 BMI (kg/m 2 ) 24.44 ± 3.67 24.53 ± 3.52 24.67 ± 3.62 Myosteatosis T-score (CT) -2.47 ± 1.41 -2.47 ± 1.30 -2.62 ± 1.62 *p < 0.05 vs. baseline.