Comparing Sequential Neoadjuvant Treatment Including Chemotherapy and Accelerated Radiation Focused to the Tumor Bed vs Neoadjuvant Chemotherapy Alone

Inclusion Criteria:

* Patients ≥ 18 years of age
* Histologically confirmed invasive carcinoma of the breast
* Patient who desires breast conservation
* Tumor stage T1N1, T2-3 N0-1
* Operable BC for which an indication for CT is determined, including T1N1 and high risk T2-3 N0-1 tumors.
* Lobular and/or ductal invasive carcinoma
* Confirmation by imaging (standard +/- MRI) of unicentric and unilateral disease
* Luminal B (defined by hormone receptor positive and grade II-III (if available from core biopsy) and Ki67 ≥ 15% or by genomic analysis) and TNG subtypes
* HER2 negative
* No distant metastases
* No contraindication for PST with anthracycline and/or taxane based regimens
* Patients with no psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule
* Signed informed consent to participate in the study must be obtained from patients after they have been fully informed of the nature and potential risks by the investigator with the aid of written information.

Exclusion Criteria:

* Patients considered too frail for CT whatever their age.
* Breast cancer clinical grade T4 and /or with major nodal involvement N2 (clinically, US, MRI or PET-CT).
* Lumpectomy is considered to be possible with an anticipated favourable cosmetic outcome considering the tumor size/breast size
* Multicentricity that would not allow BCS as confirmed by breast imaging
* Uni or bilateral inflammatory (T4d) BC
* Metastatic disease
* Other histology types: ciribriform or tubular or mucinous or epideroid carcinomas
* Her2 positive
* No signed consent to participate in the study
* Previous malignancy (except non melanoma skin cancer, thyroid carcinoma, non-invasive cancers outside the breast and patients with previous cancer in remission since more \> 5 years)
* Patients with psychological, familial, sociological or geographical conditions potentially hampering compliance with the study protocol and follow-up schedule
* Patients unwilling or unable to comply with the protocol (especially necessity to undergo breast surgery despite clinical complete response)
* Patients who have received any other investigational drugs within 30 days prior to the screening visit
* Pregnancy
* Active connective tissue disease involving the skin
* Patients with other concurrent severe and/or uncontrolled medical conditions which could compromise participation in the study .