Chemotherapy for breast cancer in pregnancy: evidence and guidance for oncologists.

It has been estimated that up to 3.8% of breast cancers may be diagnosed in women who are pregnant, with an estimated 1 in 3000-3500 deliveries occurring in women with breast cancer. Owing to the lack of large randomized trials available to guide our clinical practice, our decisions regarding adjuvant systemic management are based on retrospective analyses, case reports and a small number of prospective studies. A tailored approach to treatment is required with careful consideration given at all stages to the needs of the mother and risks to the foetus. Management is critically influenced by the stage of pregnancy, especially the first trimester. Anthracycline-based chemotherapy may be administered during the second and third trimesters, with apparently few short-term implications. Limited data shows the taxanes may also be given with few adverse events at these stages. Weekly fractionation regimens may allow closer monitoring of pregnancy with prompt termination of agents, if necessary. Data concerning the long-term risks of systemic anticancer treatment are limited. All stages of patient management should be discussed within a multidisciplinary team and a clear consensus of treatment options communicated to the mother. Delaying chemotherapy until after delivery may be reasonable in some cases, but where the delay is likely to be prolonged, a decision must be made on the basis of risks versus benefits.