When a young woman is diagnosed with breast cancer, many questions go through her mind.
What treatments does she need? Will she survive? And will she still be able to have a baby?
In a review of recent research, an international team of investigators say the answer to that critical third question is yes. Though breast cancer survivors are less likely to become pregnant than the average woman, those who do often have healthy babies and good long-term health.
"From the patient perspective, we know very well that pregnancy-related issues are really a priority of concern for these women," said Dr. Matteo Lambertini, the study's author.
Lambertini is an adjunct professor in medical oncology at the University of Genova — IRCCS Policlinico San Martino Hospital in Italy. He spends about 80% of his clinical time working with breast cancer patients age 40 and younger.
The new findings stem from a review of 39 studies that found pregnancy after breast cancer is safe and does not negatively affect a patient's prognosis, Lambertini said.
The studies included more than 114,000 breast cancer patients, including about 7,500 who had a pregnancy after a breast cancer diagnosis. Researchers assessed the frequency of pregnancies after treatment and outcomes for mother and fetus.
They found no significant increased risk of birth defects, or complications of pregnancy or delivery.
Survivors did have a 50% higher risk of having a baby with low birth weight and a 16% higher risk of having a baby small for its gestational age. Higher risks for pre-term labor and cesarean section were 45% and 14%, respectively.
Compared with breast cancer patients who did not have a subsequent pregnancy, they had a 44% lower risk of death and a 27% lower risk of their cancer recurring.
Researchers reported that pregnancy appeared safe regardless of whether a woman had the BRCA gene mutation, which increases her lifetime breast cancer risk, or whether cancer cells had invaded her lymph nodes. The amount of time between cancer diagnosis and pregnancy was also not a factor, the review found.
Compared to the general population, young women who have had breast cancer appeared to have a 60% lower chance of having a pregnancy. Researchers said it's not clear whether some of that was by choice or by doctor recommendation. The medications used to treat cancer can also be toxic to fertility.
"This is why we have to propose fertility preservation strategies and, unfortunately, not everywhere and not all women receive this type of counseling. They are not offered this type of procedure is one reason," Lambertini said.
"Still a lot of physicians believe that a pregnancy in breast cancer survivors, considering breast cancer is a hormone-driven type of tumor, it should be contraindicated," he added.
These findings may dispel some concerns, Lambertini said. They also suggest that a patient's desire for pregnancy should be considered as a component of her survivorship care plan, he said.
Counseling would involve a discussion of treatments a woman could choose to preserve future fertility. These include freezing and storing eggs or embryos. Doctors can also remove and preserve a piece of woman's ovarian tissue. A third option is a hormone shot given during chemotherapy that shuts down ovarian function.
"The ovaries are in a sort of dormant state, so they are less sensitive to the toxicity of chemotherapy," Lambertini said.
The data will be presented Thursday at the San Antonio Breast Cancer Symposium, which is being held online. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
Investigators are now researching whether a woman with a certain type of breast cancer can pause long-term endocrine therapy to get pregnant and give birth, then start therapy again.
"This really highlights the importance for doctors taking care of young women with breast cancer to discuss fertility and discuss pregnancy with these patients from the very start and, in particular, to talk about how future pregnancy appears to be feasible and safe and can be planned into the breast cancer treatment," said Dr. Erica Mayer, senior physician in the breast oncology center at Dana-Farber Cancer Institute in Boston.
Mayer, who wasn't part of the review, said she hopes these findings reassure young women who are diagnosed with breast cancer that they can take steps to help preserve fertility, if desired.
"What's really important is that this process is done as multidisciplinary teamwork and that a woman feels fully supported with this process so that she can both do her best to fight the breast cancer, but also keep working toward her goals in terms of fertility and pregnancy if that's what's on the horizon for her," Mayer said.
The nonprofit Susan G. Komen for the Cure offers additional information on planning for pregnancy after breast cancer.
SOURCES: Matteo Lambertini, MD, PhD, adjunct professor, medical oncology, University of Genova — IRCCS Policlinico San Martino Hospital, Italy; Erica Mayer, MD, MPH, senior physician, breast oncology center, Dana-Farber Cancer Institute, Boston, and assistant professor, medicine, Harvard Medical School, Boston; San Antonio Breast Cancer Symposium, online presentation, Dec. 10, 2020