Valproic Acid and Platinum-based Chemoradiation in Locally Advanced Head and Neck Squamous Cell Carcinoma

Inclusion Criteria: * Unresectable Oropharyngeal or oral cavity squamous cell carcinoma * Candidate for definitive chemoradiation * No previous treatment * Measurable disease according to RECIST v 1.1 * Previous neoplasia, other than Head and Neck, with more than five years without evidence of disease; basocellular carcinoma of the skin and in situ cervical dysplasia if resected * Age under 60 years * ECOG performance status 0-2 * Ability of understanding and giving informed consent * Adequate renal and hepatic function * Adequate bone marrow function * Normal serum magnesium * Absence of QTc prolongation * Life expectancy of over 12 weeks Exclusion Criteria: * Pregnancy * Distant metastasis * Hypersensibility to valproic acid or other antiepileptic drugs * Valproic acid chronic use * Severe neurologic impairment * Uncontrolled comorbidity * Hypoalbuminemia * Known history of hepatitis B, C or HIV