Radiation Therapy With or Without Chemotherapy in Treating Patients With High-Risk Malignant Salivary Gland Tumors That Have Been Removed By Surgery

DISEASE CHARACTERISTICS: * Pathologically proven diagnosis of a malignant major salivary gland tumor or malignant minor salivary gland tumor of the head and neck of the following histologic subtypes: * Intermediate-grade adenocarcinoma or intermediate-grade mucoepidermoid carcinoma * High-grade acinic cell carcinoma or high-grade (\>30% solid component) adenoid cystic carcinoma * Surgical resection with curative intent within 8 weeks prior to registration * All patients must have a Medical Oncology evaluation within 4 weeks prior to registration * Pathologic stage T3-4 or N1-3 or T1-2, N0 with a close (≤ 1mm) or microscopically positive surgical margin; patients must be free of distant metastases based upon the following minimum diagnostic workup: * History/physical examination within 8 weeks prior to registration * Radiologic confirmation of the absence of hematogenous metastasis within 12 weeks prior to registration; at a minimum, contrast CT imaging of the chest is required (PET/CT is acceptable) * No patients with residual macroscopic disease after surgery * No prior systemic chemotherapy or radiation therapy for salivary gland malignancy PATIENT CHARACTERISTICS: * Zubrod performance status 0-1 * Absolute neutrophil count (ANC) ≥ 1,800 cells/mm\^3 * Platelets ≥ 100,000 cells/mm\^3 * Hemoglobin ≥ 8.0 g/dL (the use of transfusion or other intervention to achieve hemoglobin ≥ 8.0 g/dL is acceptable) * Serum creatinine \< 2.0 mg/dL * Total bilirubin \< 2 x the in…