Gestational breast cancer in New South Wales: A population-based linkage study of incidence, management, and outcomes

Abstract

Background The incidence of gestational breast cancer (GBC) is increasing in high-income countries. Our study aimed to examine the epidemiology, management and outcomes of women with GBC in New South Wales (NSW), Australia. Methods A retrospective cohort study using linked data from three NSW datasets. The study group comprised women giving birth with a first-time diagnosis of GBC while the comparison group comprised women giving birth without any type of cancer. Outcome measures included incidence of GBC, maternal morbidities, obstetric management, neonatal mortality, and preterm birth. Results Between 1994 and 2013, 122 women with GBC gave birth in NSW (crude incidence 6.8/ 100,000, 95%CI: 5.6–8.0). Women aged ≥35 years had higher odds of GBC (adjusted odds ratio (AOR) 6.09, 95%CI 4.02–9.2) than younger women. Women with GBC were more likely to give birth by labour induction or pre-labour CS compared to women with no cancer (AOR 4.8, 95%CI: 2.96–7.79). Among women who gave birth by labour induction or pre-labour CS, the preterm birth rate was higher for women with GBC than for women with no cancer (52% vs 7%; AOR 17.5, 95%CI: 11.3–27.3). However, among women with GBC, preterm birth rate did not differ significantly by timing of diagnosis or cancer stage. Babies born to women with GBC were more likely to be preterm (AOR 12.93, 95%CI 8.97–18.64), low birthweight (AOR 8.88, 95%CI 5.87–13.43) or admitted to higher care (AOR 3.99, 95%CI 2.76–5.76) than babies born to women with no cancer. Conclusion Women aged ≥35 years are at increased risk of GBC. There is a high rate of preterm birth among women with GBC, which is not associated with timing of diagnosis or cancer stage. Most births followed induction of labour or pre-labour CS, with no major short term neonatal morbidity.

Perinatal outcomes of women with gestational breast cancer in Australia and New Zealand: A prospective population‐based study

“…20 Over 40% of the women with GBC included in this study had a preterm birth. Although this result is marginally lower than rates previously reported in an Italian study (50%) and a retrospective NSW data-linkage study (52%), 9,21 it is more than five times the overall rate of preterm birth in Australia. 22 Our study further revealed that the rate of preterm birth was higher among women who received systemic therapy during pregnancy compared with those who delayed treatment until after birth.…”

“…2,8 We previously analyzed population health data from New South Wales, Australia, and estimated GBC incidence as 6.8 per 100 000 women giving birth. 9 Little data are available on pregnancy and maternal morbidity and mortality associated with GBC. In Australia and New Zealand, there have been no prospective, national, population-based observational studies examining the impact of GBC management on pregnancy outcomes.…”

“…Up to one‐third of these cases are diagnosed during pregnancy (gestational breast cancer [GBC]) 2,8 . We previously analyzed population health data from New South Wales, Australia, and estimated GBC incidence as 6.8 per 100 000 women giving birth 9 …”

“… 2 , 8 We previously analyzed population health data from New South Wales, Australia, and estimated GBC incidence as 6.8 per 100 000 women giving birth. 9 …”

Risk of obstetric and perinatal complications in women presenting with breast cancer during pregnancy and the first year postpartum in Sweden 1973–2017: A population‐based matched study

“…We found no increased risks related to either surgery or chemotherapy, including for low BWGA in children exposed to maternal chemotherapy, an association which has been reported previously. 3,12,17,27 Several retrospective, single-center and multicenter studies have found a high risk of preterm birth in women with breast cancer during pregnancy, 12,13,16,18,19,[21][22][23][24][25]28 with the largest study including 462…”