Chemosensitivity During Phases of the Menstrual Cycle in Breast Cancer Patients

Exclusion Criteria

• •current use of hormonal contraception or in the six weeks prior to start of neoadjuvant systemic treatment for breast cancer, such as:
• •Oral contraception (OAC)
• •Hormonal intra-uterine device (IUD, Mirena)
• •No ovarian function suppression to preserve fertility
• •Other forms of hormonal contraception, including but not limited to: nuva-ring, Implanon, prikpil
• •Currently pregnant and / or breast feeding. In case of use of hormonal contraception or breast feeding in de last year: patients should have had at least 2 menstrual cycles since stopping hormonal contraception.
• •\- active other malignancy
• •IVF-trajectory for egg cell preservation prior to start of neoadjuvant systemic treatment