Arm Swelling Occurence in Breast Cancer Patients With Nodal Radiotherapy: Impact of Informing Them of AI-predicted Risk

Inclusion Criteria: 1. Patient must have signed a written informed consent form prior to inclusion visit and to any study specific procedures 2. Women ≥ 18 years 3. Patients with unilateral invasive breast cancer, cT1-4, cN0-N3, M0 who had undergone radical surgery defined as mastectomy or breast conservation surgery with negative margins +/- (neo)-adjuvant systemic treatment. The patient can be included no matter the status of estrogen and progesterone receptors, malignancy grade, and HER2 status 4. Axillary lymph node staging (by axillary dissection or sentinel lymph node biopsy and/or marked lymph node biopsy \[Marking Axillary lymph nodes with Radioactive Iodine seeds (MARI) procedure/ (Targeted Axillary Dissection (TAD) procedure\] in case of neo-adjuvant systemic treatment) defining the indication for regional nodal irradiation to levels I+/- II+/- III+/- IV+/- interpectoral nodes (Rotter) +/- the IMC(Internal Mammary Chain) 5. ECOG performance status 0-2 6. Patient must be randomized within the recommended time period from last surgery or the last series of chemotherapy whichever comes last as per national or institutional guidelines in order not to delay radiotherapy treatment start 7. Women of childbearing potential must agree to use adequate contraception for the duration of study participation and up to 3 months following completion of radiotherapy 8. Patient is willing and able to comply with the protocol for the duration of the clinical investigation including undergoing treatment and scheduled visits, and examinations including follow-up 9. Patient affiliated to or a beneficiary of the local social security system, health service or other local regulatory requirements Exclusion Criteria: 1. Previous breast cancer or Ductal Carcinoma in Situ (DCIS) of the ipsilateral breast 2. Bilateral breast cancer 3. Patient with previous non-breast malignancy, with the exception of cancer in complete remission for over 5 years and low risk of recurrence. Patients with the following diseases can be accepted despite less than 5 years disease free interval: carcinoma in situ of the cervix, melanoma in situ, basal cell carcinoma of the skin, squamous cell carcinoma of the skin 4. Patient who has an indication for boost to one or more regional nodes 5. Previous radiation therapy to the chest region 6. Patients having arm swelling requiring arm sleeve prescription at baseline 7. Any condition that prevents the patient from wearing a compression sleeve for 8h/day from the first day of radiation therapy until 3 months after the initiation of adjuvant radiotherapy 8. Pregnant or breastfeeding women 9. Patient already included in another therapeutic study involving radiotherapy dose/regimen/technique and/or arm lymphedema risk 10. Person deprived of their liberty or under protective custody or guardianship 11. Presence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule