Breast Cancer in Pregnancy: A Retrospective Cohort Study [24L]

INTRODUCTION: Our objective is to report pregnancy outcomes and placental histopathologic findings in women with breast cancer. METHODS: We conducted a retrospective study including pregnant women with a prior history of breast cancer and those with gestational breast cancer (GBC) managed at Mount Sinai Hospital, Toronto, Canada between 2004 and 2015. RESULTS: We identified 69 patients—47 with a prior history of breast cancer and 22 with GBC. In 21/22 cases of GBC, treatment was initiated antepartum (surgeries in 16, mean gestational age [GA] 22.5 weeks and chemotherapy in 13 [mean GA 26 weeks]). Radiotherapy was deferred until the postpartum period. There was a significant difference between groups in terms of labor induction (32.6 versus 50%, P=.045) to facilitate treatment, resulting in higher preterm birth rates (8.7% versus 63.6%, P<.0001), but no difference in GA (37.8±4.4 versus 36.3±2.0 weeks, P=.95), birthweight (3,095.2±871.2 versus 2,727±663.4, P=.43) or spontaneous vaginal deliveries (41.3% versus 59.1%). Placental histopathology was abnormal in 42.9% versus 44.4% cases. CONCLUSION: With multidisciplinary management, women with breast cancer can anticipate good pregnancy outcomes. Surgery, chemotherapy and late preterm labour induction are not associated with adverse outcomes or higher cesarean delivery rates.

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