Eligibility Criteria:
Inclusion Criteria:
* Women aged ≥ 70 yo,
* Histologically proven invasive breast cancer (regardless of the type),
* Complete surgery performed before enrolment: radical modified mastectomy or breast conservative surgery, with either a sentinel lymph node procedure or axillary lymph node dissection,
* Any N status (pN+ or pN0),
* No clinically or radiologically detectable metastases (M0),
* Oestrogen receptor (ER)-positive, as defined by a ≥ 10% tumor stained cells by immunohistochemistry (IHC),
* HER2 negative status (i.e. IHC score 0 or 1+, or IHC score 2+ and FISH/SISH/CISH negative),
* Normal haematological function: ANC ≥ 1,500/mm3; platelets count ≥ 100,000/mm3; haemoglobin \> 9 g/dl,
* Normal hepatic function: total bilirubin ≤ 1.25 ULN; ASAT and ALAT ≤ 1.5 ULN; alkaline phosphatases ≤ 3 ULN,
* Creatinine clearance (MDRD formula) ≥ 40 mL/min,
* PS (ECOG) ≤ 2,
* Patient able to comply with the protocol,
* Patients must have signed a written informed consent form prior to any study specific procedures, including the agreement for the use of archived tumoral material for genomic screening and data collection,
* Patients must be affiliated to a Social Health Insurance.
Exclusion Criteria:
* Any metastatic impairment, including homolateral sub-clavicular node involvement, regardless of its type,
* Any tumor ≥ T4a (UICC1987) (cutaneous invasion, deep adherence, inflammatory breast cancer),
* ER-negative breast cancer (i.e. \<10% tumor stained cells by IHC),
* HER2 overexpression, defined as IHC score 3+ or score 2+ and FISH/SISH/CISH positive,
* Any chemotherapy, hormonal therapy or radiotherapy for breast cancer before surgery,
* PS (ECOG) ≥ 3,
* Any specific contra-indication to the study drugs (including but not limited to hypersensitivity to the study drugs or their components),
* Patient deprived of freedom or under tutelage,
* Patient unable to comply with the required medical follow-up for geographic, social or psychological reasons.