Women who were diagnosed with breast cancer during their pregnancy may be registered in this trial.

Data is collected on the foetal outcome 4 weeks after delivery, maternal outcome of pregnancy as well as the breast cancer therapy applied (treatment, response to chemotherapy, type of surgery), diagnostic procedures applied (palpation, US, mammogram) and the outcome of mother and child after 5 years of therapy.

Breast cancer is the most common cancer malignancy in women of childbearing age after the age of 25 years. Since the incidence of breast cancer under the age of 40 is increasing, and women tend to delay pregnancy into later reproductive years, the coincidence of pregnancy and breast cancer is increasing. About 1 in 1,000 pregnancies is complicated by breast cancer. Nevertheless, little is known about the right therapy for the mother and the unborn child. We are therefore carrying out a trial, collecting prospective and retrospective data about pregnant women, with histological confirmed breast cancer. Data on the biology of the tumour and placenta tissues is also collected. The anonymous data is collected in a database.

Inclusion Criteria:

• Cohort 1: Women with histologically confirmed breast cancer during pregnancy
• Cohort 2: Patients ≤ 40 years with histological confirmed breast cancer who are not pregnant (patients who have been pregnant recently can also be collected into this cohort)
• Informed consent for data collection (for prospective participants) and biomaterial collection. For retrospective participants an informed consent is not required as long as the data are anonymously captured

Exclusion Criteria:

• Cohort 1: Diagnosis of breast cancer outside the period of pregnancy
• Cohort 2: Age at diagnosis of breast cancer > 40 years

Cohort 1: Women with histologically confirmed breast cancer during pregnancy

Cohort 2: Young women (age ≤ 40 years) with histologically confirmed breast cancer (outside of pregnancy or recently pregnant)