Phase angle assessed by bioelectrical impedance analysis in patients with colorectal cancer: a systematic review

Background Malnutrition, altered body composition, and sarcopenia are common among patients with colorectal cancer (CRC) and are associated with poor treatment tolerance and adverse clinical outcomes. PhA, derived from BIA, reflects cellular membrane integrity and body cell mass and has been increasingly investigated as a potential marker of nutritional status and prognosis in oncology. However, the clinical relevance of PhA in patients with CRC has not yet been systematically synthesized. Methods This systematic review was conducted in accordance with the PRISMA 2020 guidelines. PubMed, Embase, Web of Science, and Scopus were searched for observational studies published between January 2000 and October 2025 that assessed PhA in adult patients with CRC. Data extraction and risk-of-bias assessment using the AXIS tool were performed independently by two reviewers. Due to substantial heterogeneity in study design, outcome definitions, and PhA cut-off values, a narrative synthesis was conducted. Results A total of 10 studies involving 1,439 patients were included. Lower PhA values were consistently associated with adverse clinical outcomes. Four studies reported significantly shorter overall or progression-free survival among patients with low PhA. Four studies demonstrated associations between low PhA and unfavorable short-term outcomes, including postoperative complications, prolonged hospital stay, cancer-related complications, and early chemotherapy-related toxicity. Several studies also reported positive associations between PhA and indicators of nutritional status, body composition, muscle mass, muscle strength, and hydration balance. One longitudinal study showed that postoperative increases in PhA were accompanied by improvements in body composition parameters and reduced early chemotherapy-related toxicity. Conclusions Current evidence indicates that BIA-derived phase angle is associated with nutritional status, body composition, treatment tolerance, and survival outcomes in patients with colorectal cancer. However, heterogeneity in measurement protocols and cut-off values limits direct clinical application. Standardized assessment methods and prospective studies are needed to establish CRC-specific reference values and to determine whether interventions that improve PhA can translate into improved clinical outcomes.