Phase Angle as an Objective and Predictive Factor of Radiotherapy-induced Changes in Body Composition of Male Patients With Head and Neck Cancer.

Abstract

Unfavorable changes in body composition are frequent among patients with head and neck cancer (HNC). Unfortunately, in daily clinical practice, there is a lack of reliable diagnostic tools for predicting changes in body composition in individuals following radiotherapy (RT). Among non-invasive tools, bioelectrical impedance analysis (BIA) seems to be most promising. One BIA parameter, the phase angle (PA), reflects condition of various body cells and their mass in detail. Using BIA, the body composition was measured prior to and after RT in 52 male patients with HNC. PA derived from BIA prior to RT was tested as a predictor of body composition changes developing during RT. Patients with low PA had a greater than 9.3-fold higher chance of body mass index (BMI) reduction below 18.5 kg/m2 and over 5.9-fold and 4.2-fold higher chance of lean mass and fat mass reduction after therapy end compared with patients with a high PA value. PA values demonstrated significant diagnostic accuracy for detection of fat-free mass, lean mass and BMI reduction in the study group [area under the curve (AUC)=0.781, 0.774 and 0.786, respectively]. PA prior to RT is a useful marker for selection of individuals with HNC who are at a high risk of unfavorable changes in body composition.