Results from the largest study to date specifically designed to address several unmet questions related to the safety of pregnancy after breast cancer in women with germline BRCA mutations and their reproductive outcomes are published on 16 July 2020 in the Journal of Clinical Oncology. The study findings provide reassuring evidence that pregnancy after early breast cancer in women with germline BRCA mutations is safe without worsening of maternal prognosis and it is associated with favourable foetal outcomes. The findings are of paramount importance for healthcare providers involved in counselling young women with BRCA-mutated breast cancer who are interested about the feasibility and safety of future conception.
The authors wrote in the study background that due to current trend toward delaying childbearing, increasing numbers of young women are diagnosed with breast cancer before the completion of their reproductive plans. Pregnancy in women with a history of breast cancer is safe and does not increase the risk of recurrence, even in patients with hormone receptor–positive disease. However, very limited data are available to counsel women with germline BRCA mutations in that regard. Approximately 12% of breast cancers that arise in women younger than 40 years are related to germline deleterious mutations in BRCA1 and/or BRCA2 genes.
To investigate the impact of pregnancy on breast cancer outcomes in women with germline BRCA mutations, the authors conducted an international, multicentre, hospital-based, retrospective cohort study. Eligible were the women younger than 40 years who harboured deleterious germline BRCA mutations and have been diagnosed with early breast cancer between January 2000 and December 2012.
Primary endpoints were pregnancy rate, and disease-free survival (DFS) between women with and without a pregnancy after breast cancer. Pregnancy outcomes and overall survival (OS) were secondary endpoints.
Of 1,252 women with germline BRCA mutations from whom 811 with BRCA1, 430 with BRCA2, and 11 with BRCA1/2, 195 women had at least 1 pregnancy after breast cancer; pregnancy rate at 10 years was 19% (95% confidence interval [CI], 17% to 22%).
Induced abortions occurred in 16 women (8.2%) and miscarriages in 20 women (10.3%), respectively.
Among 150 women who gave a birth (76.9%) of 170 babies in total, pregnancy complications occurred in 13 (11.6%) and congenital anomalies in 2 (1.8%) cases.
Median follow-up from breast cancer diagnosis was 8.3 years. No differences in DFS (adjusted hazard ratio [HR], 0.87; 95% CI, 0.61 to 1.23; p = 0.41) or OS (adjusted HR, 0.88; 95% CI, 0.50 to 1.56; p = 0.66) were observed between the pregnancy and non-pregnancy cohorts.
The authors concluded that their findings provide reassuring evidence that pregnancy after early breast cancer in women with BRCA mutations is safe without worsening of maternal prognosis in terms of DFS and OS. The study team observed favourable foetal outcomes.
The study was supported by partial funding from the “Les Amis de l’Institut Bordet” foundation, the Italian Association for Cancer Research (AIRC) and the IRCCS Ospedale Policlinico San Martino (Genoa, Italy) 5×1000 grant.
Lambertini M, Ameye L, Hamy A-S, et al. Pregnancy After Breast Cancer in Patients With Germline BRCA Mutations. JCO; Published online 16 July 2020. DOI: 10.1200/JCO.19.02399.