Women with a BRCA1 or BRCA2 mutation who become pregnant after being treated for breast cancer don’t have a higher risk of breast cancer recurrence (the cancer coming back) and their babies are healthy, according to a study.
The research was published online on July 16, 2020, by the Journal of Clinical Oncology. Read the abstract of “Pregnancy After Breast Cancer in Patients with Germline BRCA Mutations.”
A germline mutation is a change in a gene that is inherited from your parents and is in all your DNA.
BRCA mutations and breast cancer
Two of the most well-known genes that can mutate and raise the risk of breast and/or ovarian cancer are BRCA1 and BRCA2. A mutation in the PALB2 gene also can increase the risk of breast and ovarian cancer.
Women who inherit a mutation in the BRCA1 or BRCA2 gene — from their mothers or their fathers — have a much higher-than-average risk of developing breast cancer and/or ovarian cancer. Men with these mutations have an increased risk of breast cancer, especially if the BRCA2 gene is affected, and possibly of prostate cancer. Many inherited cases of breast cancer have been associated with mutations in these two genes.
The function of the BRCA genes is to keep breast cells growing normally and prevent any cancer cell growth. But when these genes contain mutations that are passed from generation to generation, they do not function normally and breast cancer risk increases. Mutations in the BRCA1 and BRCA2 genes may account for up to 10% of all breast cancers, or 1 out of every 10 cases.
Pregnancy after breast cancer
Several studies, including one done by the researchers who did the study reviewed here, have found that becoming pregnant is safe for women who have been diagnosed with breast cancer, including women who have been diagnosed with hormone-receptor-positive disease. The studies showed that the women didn’t have of higher risk of recurrence. The studies also found that the women gave birth to healthy babies.
Still, few women in these earlier studies were known to have a BRCA1 or BRCA2 mutation. Also, many doctors recommend that women with a BRCA mutation have their ovaries and fallopian tubes removed in their 40s because of higher ovarian cancer risk. So women with a BRCA mutation may have to make choices about having children in a tighter timeframe than women who don’t have a BRCA mutation.
The researchers did this study to give women with a BRCA mutation more information to help them make decisions about having children after a breast cancer diagnosis.
The researchers wrote that, to their knowledge, this is “the largest study to date that investigated the impact of pregnancy on breast cancer outcomes in women harboring germline BRCA mutations.”
How the study was done
The study included 1,252 women who had a BRCA1 and/or BRCA2 mutation who had been diagnosed with breast cancer at age 40 or younger between 2000 and 2012. More than 78% of the women were European, and more than 78% were diagnosed after 2005.
- 65% of the women had a BRCA1 mutation
- 34% had a BRCA2 mutation
- 0.9% had a BRCA1 and a BRCA2 mutation
Overall, 195 of the women became pregnant after being diagnosed with breast cancer and 1,057 did not get pregnant.
Women who became pregnant after diagnosis were more likely to:
- be younger when diagnosed with breast cancer
- have a BRCA1 mutation
- be diagnosed with breast cancer that was 2 cm or smaller in size and node-negative (no breast cancer was found in the lymph nodes)
- have lumpectomy rather than mastectomy
About 95% of the women in both groups were treated with chemotherapy.
Among the women diagnosed with hormone-receptor-positive breast cancer, women who became pregnant were more likely to have had their ovarian function suppressed. This means the women took medicine to stop their ovaries from functioning while they were being treated for breast cancer. Research strongly suggests that this can help preserve fertility.
About half the women got pregnant less than 4.5 years after breast cancer treatment and half got pregnant more than 4.5 years after treatment.
Of the women who became pregnant:
- 76.9% gave birth
- 3.6% hadn’t given birth and were still pregnant at the end of the study
- 8.2% had an induced abortion
- 10.3% had a miscarriage
- the outcome was unknown for 1% of the women
Of the 170 babies who were born:
- 86.6% had no complications
- 11.6% had delivery complications
- 1.8% had a birth defect
These numbers are similar to outcomes for women in the general population who haven’t been diagnosed with breast cancer.
The researchers looked to see if there were any differences in breast cancer recurrence between women who became pregnant and women who didn’t become pregnant. There was no difference in recurrence rates.
“In conclusion, this study provides reassuring evidence that pregnancy after breast cancer in patients with germline BRCA mutations is safe without apparent worsening of maternal prognosis and is associated with favorable fetal outcomes,” the researchers wrote. “These findings are of paramount importance for health care providers involved in counseling young patients with BRCA-mutated breast cancer who inquire about the feasibility and safety of future conception.”
What this means for you
If you have been diagnosed with breast cancer and know you have a BRCA1 or BRCA2 mutation, this study is very reassuring.
The results show that becoming pregnant after being diagnosed with breast cancer doesn’t increase your risk of recurrence. The results also show that the risk of any pregnancy complications is about the same as it is for women in the general population who don’t have a BRCA mutation and who haven’t been diagnosed with breast cancer.
Every woman’s situation is unique. If you’re thinking about getting pregnant after breast cancer treatment, it makes sense to talk to your healthcare team about what’s best for you.
If you'd like to talk with others who are planning a family after treatment, join the Breastcancer.org Discussion Board forum Family and Family Planning Matters. To talk with others who have tested positive for a genetic breast cancer mutation, join the forum Genetic Testing.
Written by: Jamie DePolo, senior editor