Pregnancy does not affect disease-free survival for BRCA carriers after breast cancer

Key takeaways:

• Cumulative pregnancy incidence was 22% at 10 years after early breast cancer diagnosis.
• Women with vs. without pregnancies had significantly better breast cancer-specific survival and overall survival.

More than 20% of BRCA mutation carriers became pregnant within 10 years after receiving an early breast cancer diagnosis, and pregnancy did not affect disease-free survival, researchers reported in JAMA.

Reproductive-aged women with BRCA mutations and breast cancer diagnoses are often concerned about unique fertility challenges, according to study background.

“We previously reported preliminary results from a study including 1,252 BRCA carriers from 30 centers showing no apparent negative consequences in maternal or fetal outcomes in patients with a pregnancy after breast cancer,” Matteo Lambertini, MD, PhD, assistant professor and consultant medical oncologist at the IRCCS Ospedale Policlinico San Martino at University of Genova in Italy, and colleagues wrote. “However, the overall sample size was smaller than expected per study initial statistical assumptions and limited analyses could be performed. Hence, concerns remain regarding feasibility and safety of pregnancy in this population.”

Lambertini and colleagues conducted an international, multicenter, hospital-based, retrospective cohort study with 4,732 BRCA carrier women (median age, 35 years) from 78 participating centers worldwide. All participants were diagnosed with invasive breast cancer when aged 40 years or younger from 2000 to 2020 and carry germline pathogenic variants in BRCA1 and/or BRCA2.

The primary outcomes were cumulative pregnancy incidence after breast cancer and disease-free survival. Secondary outcomes included breast cancer-specific survival, overall survival, pregnancy, and fetal and obstetric outcomes.

Median follow-up was 7.8 years. In total, 659 BRCA carriers had at least one pregnancy after their breast cancer diagnosis. The cumulative pregnancy incidence at 10 years after diagnosis was 22% with a median timeframe of 3.5 years from diagnosis to conception.

Of all pregnancies, 6.9% had an induced abortion and 9.7% had a miscarriage. Of 79.7% completed pregnancies, 91% delivered at term and 10.4% were twin births. Of the 470 infants born with data on pregnancy complications, 0.9% had congenital abnormalities.

Researchers observed 1,683 disease-free survival events with no significant difference in disease-free survival between women with or without a pregnancy after breast cancer diagnosis. There were also 558 breast cancer-specific survival events and 609 overall survival events during the study period. Women with pregnancies had better breast cancer-specific survival (adjusted HR = 0.6; 95% CI, 0.4-0.88; P = .009) and overall survival (aHR = 0.58; 95% CI, 0.4-0.85; P = .005) compared with women without.

“Our results can inform counseling of young BRCA carriers interested in conceiving following breast cancer diagnosis,” the researchers wrote.