RecruitingNot ApplicableNCT06273800

Chemosensitivity During Phases of the Menstrual Cycle in Breast Cancer Patients

Sponsor

The Netherlands Cancer Institute

Enrollment

100 participants

Start Date

Oct 14, 2025

Study Type

INTERVENTIONAL

Conditions

Breast Cancer

Summary

This study is a prospective, multicenter study in which a serum sample will be collected at the day of starting neo adjuvant treatment in breast cancer patients

Eligibility

Sex: FEMALEMin Age: 18 YearsMax Age: 59 Years

Inclusion Criteria7

Women with a new diagnosis of triple negative breast cancer who have not yet started systemic treatment.
Patients with stage I-III disease, patient with locoregional recurrence who have not been treated with chemotherapy before. ,
Aged \< 60 years
Women having a (regular) physiological menstrual cycle
Patients who are assigned to receive neoadjuvant chemotherapy with or without immunotherapy, targeted therapy and endocrine therapy
Patients must be systemic treatment naïve for current malignancy (e.g. no chemotherapy, hormonal therapy or targeted therapy)
Signed written informed consent

Exclusion Criteria8

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