Chemoradiotherapy, Cisplatin, Head and neck cancer, Human papillomavirus, Oropharynx, Toxicity, Adult, Aged, Alphapapillomavirus, Antineoplastic Agents, Carcinoma, Squamous Cell, Cisplatin, Dose-Response Relationship, Drug, Female, Head and Neck Neoplasms, Humans, Male, Middle Aged, Oropharyngeal Neoplasms, Squamous Cell Carcinoma of Head and Neck