Study of a Strategy Integrating Adjuvant Radiation Therapy Versus Strategy Based on Monitoring in the Treatment of Carcinomas Spinocellular With High Risk of Recurrence

Inclusion Criteria: I1. Patients aged ≥ 18 years at the time of signing the informed consent form; I2. Patients with histologically confirmed localized cutaneous squamous cell carcinoma; Note: Patients with carcinoma of the external auditory canal may be included in the study; I3. Patients treated with complete surgical excision (R0), regardless of the margin (submillimeter or supramillimeter); I4. Disease with a high risk of recurrence defined by one of the following scenarios: * presence of microscopic EPN without any other risk factors; * presence of microscopic EPN with a single other risk factor; * presence of 2 risk factors other than microscopic EPN; * presence of 3 risk factors other than microscopic EPN; Note: The risk factors considered are immunosuppression (limited to untreated hematologic disease), a tumor diameter \>20 mm (longest axis, measured preferably clinically, or, failing that, histologically), a specific location (lip/ear/temple), deep invasion (tumor thickness \>6 mm (Breslow) or invasion beyond the subcutaneous fat), poor differentiation, or desmoplasia; I5. Patient informed and having signed a consent form to participate in the study; I6. Patient enrolled in a health insurance plan (or beneficiary of such a plan). Exclusion Criteria: NI1. Patients with in situ or mixed CEC; NI2. History of CEC with a high risk of recurrence in the same lymphatic drainage area (head and neck, trunk, or limb) within 2 years prior to the randomization date; NI3. History of CEC treated with systemic therapy; NI4. Patients with SCC localized to the endonasal, intraoral, anogenital, or vulvar mucosa; NI5. Patients with recurrent SCC or SCC at very high risk of recurrence defined by one of the following criteria: * EPN with ≥ 2 other risk factors, * \> 3 risk factors, * bone invasion, * immunosuppression due to immunosuppressive treatments (regardless of the reason). NI6. Patients with CEC presenting a single risk factor other than EPN; NI7. Patient with CEC and lymph node or distant metastasis; NI8. Patient with a history of cancer undergoing systemic and/or locoregional anticancer treatment; Note: Local treatment of cutaneous keratoses with fluoropyrimidines is permitted outside the theoretical radiation field); NI9. Patient with a contraindication to radiation therapy; NI10. Patient with a history of radiation therapy to the site of the lesion; NI11. Participation in another clinical trial that may interfere with the assessment of the primary endpoint; NI12. Patient under legal guardianship or conservatorship, or deprived of liberty; NI13. Pregnant or breastfeeding woman.