Direct bioimpedance
measures [resistance, reactance, phase angle] determined by bioelectrical impedance analysis (BIA) detect changes in tissue electrical properties. Bioelectrical impedance analysis vector (BIVA) technique is a promising tool, using the pure data obtained by BIA evaluation for the screening and monitoring of nutrition and hydration status. BIVA has the potential to be used as a routine method in the clinical setting for the assessment and management of body fluids. The study was conducted to evaluate soft tissue hydration and mass through pattern analysis of vector plots as height, normalized resistance, and reactance measurements by bioelectric impedance vector analysis in patients with head and neck cancer. Whole body measurements were made with ImpediMed bioimpedance analysis in 134 adult, white, male subjects 22–87 years old: 67 patients with head and neck cancer (H&NC) and 67 healthy volunteers matched by sex, age and BMI as a control group. All patients were previously untreated and without active nutritional interventions. Mean vectors of H&NC group versus the control group were characterized by an increased normalized resistance component with a reduced reactance component (separate 95 % confidence limits, P < 0.05). BIVA may offer objective measures to improve clinical decision-making and predict outcomes. In patients with H&NC to reduce post-operational complications monitoring bioimpedance vector trajectory may support therapy planning of individual patients before surgery.