SAHARA-04 : Adaptive Radiotherapy in Hypersensitive Patients and High Locoregional Risk Breast Cancer With ETHOS Technology

Inclusion Criteria: * Women ≥ 18 years old. * Conservative breast cancer surgery or radical mastectomy. * At least pN1 breast cancers, regardless breast cancer subtypes. * Tumor negative margins. * Indication of whole breast and node irradiation. * Extension evaluation of disease will be proven negative (M0). * Risk level of breast fibrosis identified by the centralized NovaGray RILA Breast® test * Must be geographically accessible for follow-up. * Written and dated informed consent. * Affiliated to the French national social security system. Exclusion Criteria: * Patients with distant metastases. * Bilateral breast cancer (concomitant or prior) except in situ lesion, either ductal or lobular, of the contralateral breast. * Patients with previous or concomitant other (not breast cancer) malignancy within the past 5 years EXCEPT adequately treated basal or squamous cell carcinoma of the skin or in situ carcinoma of the cervix. Patients who have had a previous other malignancy must have been disease free for at least five years. * Patients with other non-malignant systemic diseases (cardiovascular, renal, hepatic, lung embolism, etc.) which would prevent prolonged follow-up. * Patients treated with systemic investigational drugs within the past 30 days (Observational cohorts are accepted if the collection of data does not interfere with the current trial) * Untreated hypothyroidism * Patients known to be HIV positive (no specific tests are required to determine the eligibility). * Patients known as hypersensitive to radiation (ATM Homozygote, p53-/-,…) * Pregnant or breast-feeding women * Patient unable to comply with study obligations for geographic, social, or physical reasons, or who is unable to understand the purpose and procedures of the study * Person deprived of their liberty or under protective custody or guardianship.