Fulvestrant Versus Fulvestrant Plus Palbociclib in Operable Breast Cancer Responding to Fulvestrant

Inclusion Criteria: 1. Written informed consent prior to beginning specific protocol procedures including expected cooperation of the patients for the treatment and follow-up must be obtained and documented according to the local regulatory requirements. 2. Age \>18. 3. Postmenopausal women or pre-menopausal (with medical or surgical oophorectomy) 4. Performance status \< 2 (according to WHO criteria). 5. Histologically confirmed non-metastatic breast cancer (Luminal A or B) * HR (hormone receptor ) positive (Estrogen or Progesterone)\> 1%. * Her-2 negative (score 0 or 1 by immunochemistry), FISH (fluorescence in situ hybridization) negative if IHC (immuno-histochemistry) score 2). 6. Clinical stage II and IIIa. 7. No previous breast cancer treatment by surgery, radiotherapy, hormone therapy or chemotherapy. 8. Measurable or evaluable disease. 9. Hematology: * Neutrophil count ≥ 1.5 G/L. * Platelet count ≥ 100 G/L. * Leucocyte count \> 3.0 G/L. * Hb\> 9g/dl. 10. Hepatic function: * Total bilirubin ≤ 1.5 time the Upper Normal Limit (UNL). * ASAT (alanine aminotransferase aspartate transaminase ) ≤ 2.5xUNL. * ALAT (alanine aminotransferase) ≤ 2.5xUNL. * Alkaline phosphatase ≤ 2.5 time the upper normal limit (UNL). 11. Renal function: * Serum creatinine ≤1.5xUNL (and if Serum creatinine \>1.5xUNL, creatinine clearance ≥50 mL/min). * Creatinine clearance ≥40 mL/min in case of MRI. 12. Metabolic function: * Serum magnesium ≥ lower limit of normal. * Serum calcium ≥ lower limit of normal. 13. No progressive heart disease and no anthracycline contraindication (normal LVEF ( left ventricular ejection fraction) according to the institution guidelines). 14. Negative pregnancy test (urine or serum) within 7 days prior to registration for all women of childbearing potential. Patients of childbearing potential must implement adequate non-hormonal contraceptive measures during study treatment. Exclusion Criteria: 1. Male patients. 2. Her-2 positive tumors or unknown HR/Her-2 status. 3. Pregnancy or breast-feeding, or plan to become pregnant within 6 months post treatment. 4. No willingness to use highly effective methods of contraception (per institutional standard) during treatment and for 6 months post treatment. 5. Any form of breast cancer other than those described in the inclusion criteria, particularly inflammatory and/or overlooked forms (stages IIIb or IV). 6. Non-measurable tumour. 7. Bilateral breast cancer. 8. Previous treatment for breast cancer including surgery for their disease or have had primary axillary dissection, radiotherapy and systemic therapy. 9. Patient with history of other cancer, except in situ cervical cancer or baso-cellular skin cancer, considered cured. 10. Patient has another disease, which is deemed incompatible with the inclusion in the protocol. 11. Heart, kidney, medullary, respiratory or liver failure. Clinically significant cardiovascular disease (including myocardial infarction, unstable angina, symptomatic congestive heart failure, serious uncontrolled cardiac arrhythmia) ≤ 1 year before enrollment in the study. * History of interstitial lung disease e.g. pneumonitis or pulmonary fibrosis or evidence of interstitial lung disease at baseline * Acute urinary infection, ongoing hemorrhagic cystitis. 12. Uncontrolled diabetes. 13. Symptomatic or progressive disorder of the central nervous system (CNS) Peripheral neuropathy \> grade 2 14. Significant psychiatric abnormalities. 15. History of hypersensitivity to studied treatment or excipients 16. Known previous or ongoing abuse narcotic drug, other medication or alcohol 17. Any investigational agent within 30 days before initiation of study treatment. 18. No major surgical procedure within 28 days of initiation of treatment. 19. Subject unwilling or unable to comply with study requirement.