GM-CSF Mouthwash for Preventing and Treating Mucositis in Patients Undergoing Radiation Therapy for Head and Neck Cancer

Inclusion Criteria * Histopathologically confirmed diagnosis of head and neck cancer * Scheduled to undergo continuous course of conventional or hyperfractionated radiotherapy or intensity-modulated radiotherapy (IMRT) with or without concurrent chemotherapy * Planning to receive a total radiation dose ≥ 5,500 centigray (cGy), administered in a single daily fraction of 180-220 cGy (5 days a week) or twice daily fractions of 110-150 cGy * Normal baseline oral examinations (no pre-existing lesion) * Karnofsky performance status 60-100% * Mentally capable of participating in research protocol * Expected survival \> 4.5 months * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Creatinine ≤ 2.0 mg/dL * Bilirubin ≤ 2.0 mg/dL * Aspartate aminotransferase (AST) \< 5 times upper limit of normal * HIV negative Exclusion Criteria * No unresolved adverse event from previous therapy * No prior radiotherapy to the head and neck * No prior or concurrent brachytherapy * No prior participation in this study * No T1 or T2 glottic tumors * No other serious concurrent medical illness * No history of insulin-dependent diabetes mellitus * No prior hypersensitivity reaction to yeast material * No recent history of oral ulceration, herpes simplex, oral candidiasis, severe gingivitis, active or chronic mucositis, or xerostomia * No current New York Heart Association class II-IV congestive heart failure * Not pregnant or nursing * No chemotherapy, radiotherapy, or other in…