medwireNews: Women with breast ca ncer and germline pathogenic variants in BRCA1 and/or BRCA2 can be reassured by the results of a large global study that suggest no apparent detrimental effect of postcancer pregnancy on maternal prognosis or fetal outcomes, say researchers.
“This study showed that more than 1 in 5 young BRCA carriers became pregnant following diagnosis of early breast cancer and that disease-free survival was comparable with those who did not become pregnant,” they write.
“Our results can inform counseling of young BRCA carriers interested in conceiving following breast cancer diagnosis,” continue Matteo Lambertini (University of Genova–IRCCS Ospedale Policlinico San Martino, Italy) and fellow investigators in JAMA.
They explain that “while several studies have demonstrated the safety of conceiving following treatment completion for breast cancer, the evidence for BRCA carriers is very limited.”
The team therefore conducted an international cohort study that included 4732 women who harbored germline pathogenic variants in BRCA1 and/or BRCA2 and were diagnosed at the age of 40 years or younger (median 35 years) with invasive breast cancer at one of 78 centers worldwide during 2000–2020.
Of these, 659 women had at least one pregnancy after breast cancer, while the remaining 4073 did not. The cumulative incidence of pregnancy at 10 years was 22%, with a median time to conception from breast cancer diagnosis of 3.5 years. Most (79.2%) of the pregnancies were spontaneous, with just 20.8% requiring the use of assisted reproductive technology.
Among the participants who became pregnant, 6.9% had an induced abortion and 9.7% had a miscarriage. The majority (91.0%) of women with a completed pregnancy delivered at term (≥37 weeks) and 10.4% had twins.
A total of 470 infants were born to patients with known information on pregnancy complications, and congenital abnormalities (eg, cardiac malformation) were documented in 0.9% of these and fetal complications (eg, respiratory distress) in 0.6%.
With regard to maternal survival outcomes, there was no significant association between pregnancy and the occurrence of disease-free survival (DFS) events, report Lambertini and colleagues.
And in fact, pregnancy appeared to be significantly associated with a lower incidence of breast cancer-specific survival events, at an adjusted hazard ratio (HR) of 0.60, and a lower rate of all-cause death, at an HR of 0.58.
“Results from our study, in which 80.1% of pregnancies occurred more than 2 years after diagnosis, provide evidence in the specific cohort of young BRCA carriers with a rate of pregnancy complications that are in line with the expectations in a population of women with similar age and no history of breast cancer,” say the study authors.
But they point out that “[t]he majority of information for this analysis was extracted from oncology medical records,” and “[t]hese records are not specifically designed for recording maternal or fetal outcomes; hence, there is a potential risk of underreporting of adverse pregnancy outcomes and the data should be considered with caution.”
Lambertini and co-authors also note that subgroup analyses showed a significant interaction between pregnancy and the specific BRCA gene, such that pregnancy was associated with a lower DFS event rate among women with BRCA1 mutations, but those with BRCA2 mutations appeared to have a potential increased risk for events (HRs=0.80 and 1.55, respectively).
“Thus, while the results appear reassuring for BRCA1 carriers, more caution is needed to counsel BRCA2 carriers,” they comment.
The findings were presented simultaneously at the 2023 San Antonio Breast Cancer Symposium in Texas, USA.
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JAMA 2023; doi:10.1001/jama.2023.25463
San Antonio Breast Cancer Symposium; Texas, USA: 5–9 December 2023