Bioelectrical impedance phase angle in clinical practice: implications for prognosis in advanced colorectal cancer.

BACKGROUND Phase angle, determined by bioelectrical impedance analysis (BIA), detects changes in tissue electrical properties and has been found to be a prognostic indicator in several chronic conditions-such as HIV, liver cirrhosis, chronic obstructive pulmonary disease, and lung cancer-and in patients receiving dialysis. OBJECTIVE This study was conducted to investigate the prognostic role of phase angle in advanced colorectal cancer. DESIGN We evaluated a case series of 52 patients with histologically confirmed stage IV colorectal cancer. BIA was conducted on all patients and phase angle was calculated. The Kaplan-Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle independent of other clinical and nutritional variables. RESULTS Patients with a phase angle < or =5.57 had a median survival of 8.6 mo (95% CI: 4.8, 12.4; n=26), whereas those with a phase angle >5.57 had a median survival of 40.4 mo (95% CI: 21.9, 58.8; n=26; P=0.0001). CONCLUSION Phase angle is a prognostic indicator in patients with advanced colorectal cancer. Similar studies of other cancer types with larger sample sizes are needed to further validate the prognostic significance of phase angle in cancer treatment settings.