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

Abstract

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.

Association of pregnancy and mortality in women diagnosed with breast cancer: A Nationwide Population Based Study in Taiwan

“…Compared to those who completed pregnancy, the adjusted HR o was 0.62 (95% CI = 0.06–6.38) for those who aborted. Current evidence suggests that chemotherapy improved the material prognosis and chemotherapy during the second and third trimesters of pregnancy were safe for the fetus . However, some of the babies may still experience complications, such as small for gestational age, preterm birth or neonatal intensive care unit admission .…”

“…The current standard treatments for pregnancy-related breast cancer include surgery during all trimesters 43 and neoadjuvant and/or adjuvant chemotherapy from the second trimester. 18,[44][45][46] Among the 90 pregnant patients, 26 fetuses were aborted (including spontaneous and induced abortion), and 3 mothers were dead. Four other mothers were dead after delivery.…”

The role of imaging techniques in the diagnosis, staging and choice of therapeutic conduct in pregnancy associated breast cancer

“…After 14 weeks of pregnancy the possibility of such complications decreases to an acceptable level (between 1.5-3%) [32].…”

Fertility and breast cancer

“…However, when chemotherapy is used in the second and third trimester the rate of congenital malformations is not higher than the baseline population risk of approx. 3% [7] In contrast, tamoxifen is associated with a significantly higher risk of pregnancy complications and foetal defects than that of the general population [9]. Apart from modulating oestrogen receptors, the drug may, similarly to clomiphene, induce ovulation in women who are infertile due to ovulation disorders.…”