Carcinoma, Squamous Cell/chemistry; Head and Neck Neoplasms/chemistry; Metallothionein/analysis; Neoplasm Proteins/analysis; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols/chemistry; Antineoplastic Combined Chemotherapy Protocols/therapeutic use; Carboplatin/administration & dosage; Carcinoma, Squamous Cell/drug therapy; Carcinoma, Squamous Cell/pathology; Carcinoma, Squamous Cell/radiotherapy; Cell Differentiation; Chemotherapy, Adjuvant; Cisplatin/administration & dosage; Combined Modality Therapy; Drug Resistance, Neoplasm; Female; Fluorouracil/administration & dosage; Gingival Neoplasms/chemistry; Gingival Neoplasms/pathology; Gingival Neoplasms/therapy; Head and Neck Neoplasms/drug therapy; Head and Neck Neoplasms/pathology; Head and Neck Neoplasms/radiotherapy; Humans; Hypopharyngeal Neoplasms/chemistry; Hypopharyngeal Neoplasms/pathology; Hypopharyngeal Neoplasms/therapy; Lymphatic Metastasis; Male; Maxillary Sinus Neoplasms/chemistry; Maxillary Sinus Neoplasms/pathology; Maxillary Sinus Neoplasms/therapy; Middle Aged; Mouth Mucosa/chemistry; Tongue Neoplasms/chemistry; Tongue Neoplasms/pathology; Tongue Neoplasms/therapy; Treatment Outcome