Schéma : The aim of the study is to perform a French multicenter prospective interventional study in order to assess the feasibility and safety of ovarian hyperstimulation for oocyte / embryo cryopreservation in young women with breast cancer. The oncologic and reproductive benefit / risk ratio will be investigated in the oncology and reproductive area.

Medical Oncology:
Information and collection of consent,
Imaging staging,
Inclusion
Physical examination
Contraception advise given

Reproductive medicine center:
Ovarian reserve assessment: serum anti-mullerian hormone (AMH) measurement and antral follicle count (AFC) by ultrasound.
Serology syphilis, hepatitis B and C, HIV (human immunodeficiency virus). In case of embryo cryopreservation, same serology determination for the men.
Infertility risk and fertility preservation techniques information.
In case of agreement, this technique will be done during the time-interval between surgery and chemotherapy
Fertility preservation (COH stimulation, triggering and oocyte retrieval)

Adjuvant chemotherapy:
The chemotherapy regimen is 3 FEC (fluorouracil epirubicin cyclophosphamide) 100 followed by 3 Docetaxel +/- Trastuzumab. Adjuvant chemotherapy may only begin after the oocyte retrieval.
Usual adjuvant chemotherapy is not changed

During chemotherapy:
Clinical exam before each cycle of chemotherapy
AMH, AFC at cycle 6

After chemotherapy:
Usual patient monitoring in expert center : physical examination at Month 3 (M3), M6 M9 M12 M18 and M24 and mammography at M9 then annual
AMH at Month 3 (M3), M6 M9 M12 M18 and M24
AFC at Month 12 (M12) and M24