P1.129. Predictive Value of Baseline Bioelectrical Impedance Analysis(BIA) for Chemoradiotherapy Completion in Locally Advanced Esophageal Cancer: Implications for Prehabilitation

Abstract

Abstract Topic Esophageal Cancer: Oncology/Radiation Therapy Background Locally advanced esophageal cancer requires toxic chemoradiotherapy, yet no established pretreatment body composition thresholds exist to predict completion. Traditional assessment relies on subjective performance status, often overlooking occult sarcopenia. This study evaluates BIA markers against BMI to define objective cut-offs for guiding targeted prehabilitation and optimizing therapeutic resilience. Methods A retrospective cohort study analyzed patients with locally advanced esophageal cancer undergoing definitive or neoadjuvant CCRT at a provincial tertiary center in Thailand from December 2023 to October 2025. Baseline body composition was assessed using direct segmental multi-frequency bioelectrical impedance analysis immediately post-diagnosis. Patients were categorized into "Completion CCRT" (n=30) and "Non-completion CCRT" (n=11; withdrawal, loss to follow-up, early mortality) treatment groups. We compared baseline BMI, PhA, SMI, and other body composition parameters between groups using independent t-tests and Mann-Whitney U tests to identify predictors of treatment resilience. Results Forty-one patients (mean age 60.3±10.3; 95.1% male; 97.6% SCC) were included. The CCRT completion rate was 73.2% (30/41). While the Non-completion CCRT group had significantly lower weight (39.7 vs 47.5 kg, p=0.002) and BMI (15.0 vs 17.4 kg/m2, p=0.009), BIA revealed critical underlying deficits. The Non-completion group demonstrated significantly depleted Skeletal Muscle Index (5.43 vs 6.22 kg/m2, p=0.006), Fat Mass (4.4 vs 7.3 kg, p=0.033), and Basal Metabolic Rate (1132 vs 1246 kcal, p=0.003). Although Phase Angle was lower in the Non-completion group (4.68° vs 5.29°), it did not reach statistical significance (p=0.274). These findings characterize a state of severe cachexia driving treatment failure. Conclusion Baseline BIA parameters effectively identify high-risk phenotypes driving CCRT failure. While validation in larger cohorts is warranted, future research should focus on monitoring BIA dynamics following nutritional interventions. Ultimately, this study serves as a pivotal foundation for implementing targeted prehabilitation, aiming to optimize physiological resilience and ensure treatment completion in locally advanced esophageal cancer.