Multimodal Prediction of Response to Chemoradiotherapy for Squamous Cell Carcinoma of the Head and Neck

Inclusion Criteria: * Patient with squamous cell carcinoma of the oropharynx (cT2-cT4) or squamous cell carcinoma of the oral cavity (cT2-cT4) * With lymph node involvement (cN1, cN2, or cN3) (confirmation of lymph node involvement after review of imaging in CCP and without histological confirmation required) * Eligible for curative treatment with cisplatin-based chemoradiotherapy alone (100 mg/m2 every 3 weeks or 40 mg/m2 weekly) * Regardless of p16 status * Affiliated with or covered by a social security system Exclusion Criteria: * Head and neck squamous cell carcinomas in other locations (salivary gland, larynx, hypopharynx, cavum, sinuses) * Primary squamous cell carcinoma of the lymph nodes * History of radiotherapy to the head and neck region * Radiochemotherapy not based on the use of cisplatin * Pregnant or breastfeeding women * History of invasive cancer in the last 3 years (except for Breslow melanoma less than 1 mm) * Contraindication to MRI, CT, or PET/CT * Allergy or contraindication to iodine, gadolinium, or 18F-FDG * Uncontrolled diabetes (fasting blood glucose greater than 12 mmol/l) * Patients unable to understand the study for any reason or to comply with the trial requirements (language, psychological, geographical issues, etc.) * Patients under guardianship or conservatorship * Patients deprived of their liberty by judicial or administrative decision * Patients undergoing psychiatric care that renders them incapable of giving their consent * Patients admitted to a health or social care facility for purposes other than research