Bioelectrical Impedance Analysis in Estimating Body Composition in Patients With Stage I-IV Head and Neck Cancer Undergoing Radiation Therapy

Inclusion Criteria: * Histologically documented head and neck cancer (clinical stage I-IVB; Tx,1-4, N0-3). * Patients dispositioned to receive radiation therapy (dose \>= 60 gray \[Gy\]). * Patients may receive radiation as either primary therapy or post-operatively. * Patient received staging positron emission tomography/computed tomography (PET/CT) scan during 60-day period prior to initiating therapy. * Negative pregnancy test for women of child bearing potential. Exclusion Criteria: * Previous radiation treatment for head and neck mucosal primary cancers (i.e. oropharynx, nasopharynx, hypopharynx, larynx, and oral cavity). * Patients with pacemaker, implanted cardiac defibrillator, or vagal nerve stimulator. * Pregnant or breast-feeding females. * Patients weighing over 660 lbs (300 kg). * Patients with other medical conditions known to cause sarcopenia, including New York Heart Association (NYHA) class III-IV heart failure, oxygen-dependent pulmonary disease, advanced human immunodeficiency virus infection, cirrhosis, end stage renal disease, or inherited/congenital disorders of metabolism. * Patients receiving palliative irradiation.