Gestational breast cancer: maternal and baby outcomes

University of Technology Sydney. Faculty of Health.The incidence of gestational breast cancer (GBC), also called breast cancer diagnosed during pregnancy, is rising. GBC presents unique challenges in clinical management to optimise outcomes for mothers and their babies. To examine the perinatal outcomes of women with GBC to create an evidence-base to assist health care providers in clinical management. The main objectives were: to describe the incidence, management, and perinatal outcomes of women with GBC, to investigate factors affecting their survival, to explore the safety of options available to healthcare providers for diagnosing GBC, and to describe the outcomes of babies exposed to GBC systemic treatment. Four studies were conducted using population-based data sets. Studies 1 and 2 utilised New South Wales (NSW) data to investigate all women with pregnancies that ended in live birth or stillbirth between 1 January 1994 and 31 December 2013. Studies 3 and 4 utilised data from the Australasian Maternity Outcome Surveillance System GBC study collected in Australia and New Zealand between 1 January 2013 and 30 June 2014. Studies 1 and 2: The annual incidence of GBC in NSW was 6.8/100,000 women. Women with GBC were more likely to give birth by labour induction or pre-labour caesarean section (CS) than women with no cancer (adjusted odds ratio (AOR) 4.8, 95%CI: 2.96–7.79). Babies born to women with GBC were more likely to be preterm (AOR 12.93, 95%CI: 8.97–18.64) and low birthweight. Of 122 women identified with GBC, 19.7% died within five years of diagnosis. The mortality rate for women with stage 4 cancer at diagnosis was 1,446/10,000 person-years, which is higher than that for women with stages 2 and 3 (399/10,000 person-years) or stage 1 (222/10,000 person-years). Studies 3 and 4: 83% of women with GBC experienced a painless breast lump. Breast ultrasound was the first-line imaging modality in all women. Eighteen babies exposed to breast cancer systemic treatment during pregnancy were born. None had a congenital malformation or major neonatal morbidity. There was a high rate of preterm birth among women with GBC. Most births followed induction of labour or pre-labour CS. The crude 5-year mortality observed for women with GBC was 19.7%, which is almost double that previously reported for all women diagnosed with breast cancer in Australia. GBC diagnosed during mid-pregnancy and treated with chemotherapy was associated with a high rate of planned preterm birth but no increase in perinatal mortality