Patients including of localized breast cancer will require chemotherapy treatment with epirubicin - cyclophosphamide (EC) followed by treatment with docetaxel or paclitaxel. In addition to this chemotherapy, the investigator will prescribe injections of granulocyte growth factors (G-CSF), to stimulate the growth of white blood cells. Patients will be randomized to either a peg-G-CSF arm or a G-CSF arm, prescribed at different times.

The aim is to determine whether one of the two treatment regimens best limits the risk of a decrease in white blood cells

For this tudy : patients will be randomized to either :

• with administration of peg-G-CSF (administration on D2)
• with administration of G-CSF (administration on D4 to D7 or D8)

This study aims to model the effect of exogenous G-CSF for the evolution of polymorphonuclear neutrophils as a function of time and to explain the pharmacodynamic variability during the administration of chemotherapy such as EC-dense dose administered as an adjuvant or neo-adjuvant in patients treated for localized breast cancer.

Inclusion Criteria:

• Women
• Patient over 18 years old
• Patient with histologically documented, non-metastatic breast cancer who must receive dense dose Epirubicin-Cyclophosphamide (EC) type treatment as part of neoadjuvant or adjuvant treatment
• Patient to receive granulocyte growth factors (G-CSF or peg-G-CSF) as a preventive measure from the first cycle
• Neutrophils > 1,500 /mm3; platelets > 100,000 /mm3
• Written informed consent, dated and signed
• For patients of childbearing age, effective means of contraception during treatment and up to 3 months after stopping treatment

Exclusion Criteria:

• Patient with a contraindication to treatment with anthracyclines
• Patient already undergoing treatment with EC dense dose
• Patient with a contraindication to treatment with G-CSF such as hypersensitivity to the active ingredient or to one of the excipients
• Pregnant or breastfeeding women
• Patient under guardianship or curatorship or subject to a protection regime for adults
• Patient not affiliated to a social security scheme (beneficiary or beneficiary)

First inclusion criterion : Women