Breast Cancer in Pregnancy: A Retrospective Cohort Study.

Gestational breast cancer (GBC) is the second most commonly occurring malignancy affecting pregnant women. Management is complex due to potential foetal risks in the setting of maternal treatment. We report on the maternal, foetal, short-term neonatal and placental histopathologic findings of a retrospective cohort of pregnant women with either pre-gestational (group 1) or GBC (group 2) from a tertiary-level maternity care centre. Of the 69 women identified over 12 years, there were 47 in group 1 and 22 in group 2. Demographics, stage of breast cancer at diagnosis were similar in the 2 groups. Women with GBC (group 2) were more likely to receive surgery and chemotherapy or surgery alone as compared to those in group 1. No women with GBC received radiation during pregnancy, but 2 received this treatment postpartum. With regard to pregnancy outcomes, induction of labour was more common in women with GBC, as was preterm birth. Most preterm birth in women with GBC was late preterm, iatrogenic in nature to facilitate postpartum treatment. We conclude comparable pregnancy outcomes for women with GBC as compared to those with pregestational breast cancer.