• Recurrence or second primary of HNSCC in a previously irradiated area at a dose ≥ 50 Gys

• HNSCC of oral cavity, oro and hypopharynx, larynx only if extralaryngeal spread (rT4), isolated nodal recurrence

• Patient who has received salvage surgery with curative intent and macroscopic complete resection:

• for cohorts 1 and 2: similarly to inclusion criteria of previous reirradiation trials, more than 6 months between radiotherapy and salvage surgery

• for cohorts 1bis and 2bis: less than 6 months between radiotherapy and salvage surgery

• Recurrence of bad prognosis justifying an adjuvant treatment:

• clinically infiltrative recurrence or second primary; or nodal recurrence upper or equal to 3 cm, or association of local and nodal recurrence;

• superficial recurrence, but histologic gravity signs on surgical specimen indicating a high risk of recurrence after salvage surgery (histologic involvement of surgical margins or margins less than 3mm, perineural spread or vascular emboli, multiples invaded nodes). Nodal recurrence without tumor recurrence and inferior to 3cm, but with capsular rupture at histologic examination.

• Sufficient healing for beginning adjuvant treatment within 8 weeks (+/- 2 weeks) of salvage surgery

• No distant metastases, confirmed by CT or PET scan

• Male and female between 18 and 75 years (included)

• ECOG 0 or 1

• Immunosuppressive doses of systemic medication, such as steroids or absorbed topical steroids (doses \> 10 mg/day prednisone or equivalent) must be discontinued at least 2 weeks before study drug administration

• Screening laboratory values must meet the following criteria (using CTCAE v4) and should be obtained within 14 days to the administration of the first study treatment.: WBC \> 2,000/μL. Polynuclear neutrophils \>1.5 x 10\^9/L. Platelets \> 75 x 10\^9/L. Hemoglobin \> 8.0 g/dL. ALAT/ASAT\< 3.0 x ULN. Bilirubin \< 1.5 x ULN (except Gilbert Syndrome

• : \< 3.0 mg/dL). Creatinine clearance \> 40 mL/min (measured or calculated by Cockroft and Gault formula) or serum creatinine \< 2.0 x ULN

• Women of childbearing potential must have a negative serum β-HCG pregnancy test within 24 hours prior to the administration of the first study treatment.

• Sexually active women of childbearing potential must agree to use a highly effective method of contraception or to abstain from sexual activity during the study and for at least 5 months after the last study treatment administration. Sexually active males patients must agree to use condom during the study and for at least 7 months after the last study treatment administration. Also, it is recommended their women of childbearing potential partner use a highly effective method of contraception.

• Women who are breastfeeding should discontinue nursing prior to the first dose of study drug and until 5 months after the last dose.

• Patient should understand, sign, and date the written informed consent form prior to any protocol-specific procedures performed. Patient should be able and willing to comply with study visits and procedures as per protocol.

• Patients must be affiliated to a social security system or beneficiary of the same