Breast cancer is one of the most common malignancies of women in the reproductive years. In the Western world there is a trend towards delaying pregnancy to later in life and in combination with an increased incidence of breast cancer an increased number of women are diagnosed with breast cancer before they have completed their reproductive plans. In addition, breast cancer during pregnancy may affect an increased number of women as the childbearing years are delayed. The survival rate after breast cancer has improved during the last decades and many young breast cancer survivors will consider a pregnancy subsequent to the completion of adjuvant breast cancer therapy. Traditionally, many women are advised against a pregnancy due to a fear of increased risk of recurrence, especially women with estrogen receptor positive breast cancer. Due to feasibility issues, evidence from large prospective randomized trials are missing regarding the safety of pregnancy after breast cancer. Today guidelines are based on cohort studies and population-based registry evidence with its limitations. Overall, data suggest that pregnancy after breast cancer therapy is safe and the current evidence is summarized in this overview.Keywords: breast cancer, mammary cancer, pregnancy, estrogen receptor, fertility 3
Key messages: Despite the lack of high-level evidence all retrospective data report no unfavorable effect on breast cancer outcome of a subsequent pregnancy after adjuvant breast cancer therapy. There are no reasons for proscription in principle against pregnancy for women after breast cancer therapy. The risk of premature menopause, infertility, and the suitability of fertility preservation approaches need to be discussed in a multidisciplinary setting with all eligible women before start of cytotoxic therapies. Women with breast cancer during pregnancy should be given appropriate systemic treatment as closely as possible to general guidelines.4