Pregnancy after breast cancer in patients with germline BRCA mutations

July 24, 2020

The study in the Journal of Clinical Oncology is a follow-up to a study conducted by the same authors to evaluate if pregnancy is safe in breast cancer patients who have hormone-sensitive breast cancer.

An international, multicenter, hospital-based, retrospective cohort study has found that pregnancy after breast cancer in patients with germline BRCA mutations is safe, without apparent worsening of maternal prognosis, and results in favorable fetal outcomes.1

The study in the Journal of Clinical Oncology is a follow-up to a study conducted by the same authors to evaluate if pregnancy is safe in breast cancer patients who have hormone-sensitive breast cancer.

“In the former study, we reported for the first time that pregnancy does not appear to have a detrimental impact on the outcome of women with a history of hormone-sensitive breast cancer,” Dr. Azim told Contemporary OB/GYN.

The authors wanted to pose the same question in patients with breast cancer who had germline mutation in the BRCA1/BRCA2 gene, as the latter occurs more often in young patients.

Those women often are confronted with unique fertility challenges in terms of the question about whether future pregnancy increases the risk of breast cancer recurrence.

In preparation for the current study, the investigators conducted a survey involving more than 250 breast cancer specialists, which indicated that roughly 50% were concerned about the safety of pregnancy after breast cancer in women harboring germline BRCA mutations.

“This underscored the need to conduct a definitive trial to address these concerns,” Dr. Azim said.

Eligible patients were diagnosed between January 2000 and December 2012 with invasive early breast cancer at age 40 or younger and harbored deleterious germline BRCA mutations.

On the 1,252 patients with germline BRCA mutations, 811 were BRCA1, 430 were BRCA2 and 11 were BRCA1/2. In total, 195 patients had at least one pregnancy after breast cancer, with a 19% pregnancy rate at 10 years (95% confidence interval [CI]: 17% to 22%).

Induced abortions and miscarriages occurred in 8.2% (n = 16) and 10.3% (n = 20) of patients, respectively. Pregnancy complications and congenital anomalies occurred in 11.6% (n = 13) and 1.8% (n = 2) of cases, respectively.

The median follow-up after breast cancer diagnosis was 8.3 years. No difference was observed between the pregnancy and nonpregnancy cohorts in disease-free survival: adjusted hazard ratio (HR) = 0.87; 95% CI: 0.61 to 1.23 (P = 0.41). Nor was there a difference detected in overall survival: adjusted HR = 0.88; 95% CI: 0.50 to 1.56 (P = 0.66).

“This study shows for the first time that future pregnancy in women with BRCA-mutated breast cancer does not increase their risk of breast cancer recurrence, which is rather reassuring,” Dr. Azim said. “In addition, the pregnancy and fetal outcomes appear to be largely comparable to what is expected in the general population.”

Although Dr. Azim is not surprised by the study’s findings, he suspects those in oncology will be, based on the prior survey.

“It is estimated that around 12% of all breast cancer patients below age 40 have a BRCA mutation,” Dr. Azim said.

“Given the rising trend of delaying childbearing, it is now more frequent for clinicians to encounter women who were diagnosed with breast cancer before completing their families. This study provides a clear answer to all those women who are willing to become pregnant after cancer diagnosis, but are concerned that their pregnancy places their tumor at risk.”

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Dr. Azim reports no relevant financial disclosures.

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Reference
  1. Lambertini M, Ameye L, Hamy A-S, et al. Pregnancy after breast cancer in patients with germline BRCA mutations. J Clin Oncol. Published online July 16, 2020. doi:10.1200/JCO.19.02399