Pregnancy after breast cancer safe for BRCA carriers

One in five young BRCA carriers with breast cancer subsequently conceive within 10 years, without any detrimental effect on disease-free survival, according to a study.

For the study, researchers looked at 4,732 BRCA carriers (median age 35 years) diagnosed with invasive breast cancer at age 40 years or younger and were carrying germline pathogenic variants in BRCA1 and/or BRCA2. Primary endpoints were cumulative incidence of pregnancy after breast cancer and disease-free survival. Breast cancer–specific survival, overall survival, pregnancy, and foetal and obstetric outcomes were also assessed as secondary outcomes.

A total of 659 participants had at least one pregnancy after breast cancer, including 45 (6.9 percent) who had an induced abortion and 63 who had a miscarriage (9.7 percent). Cumulative incidence of pregnancy at 10 years was 22 percent (95 percent confidence interval [CI], 21–24), with a median time from breast cancer diagnosis to conception of 3.5 years.

Of the 517 participants (79.7 percent) with a completed pregnancy, 406 (91.0 percent) delivered at term (≥37 weeks) and 54 (10.4 percent) had twins. Four (0.9 percent) of the 470 infants born with known information on pregnancy complications had documented congenital anomalies.

Over a median follow-up of 7.8 years, disease-free survival did not significantly differ between participants who had and those who had no pregnancy after breast cancer (adjusted hazard ratio, 0.99, 95 percent CI, 0.81–1.20). Of note, those who had a pregnancy had more favourable breast cancer–specific survival and overall survival outcomes.