Many women diagnosed with breast cancer, especially younger women, are concerned about their ability to have children after treatment. Some breast cancer treatments can cause temporary infertility or make it harder to get pregnant after treatment ends. Other treatments, especially certain chemotherapy regimens, can cause early menopause and infertility.
A study has found that freezing embryos created from eggs extracted before treatment allowed women diagnosed with early-stage breast cancer treated with chemotherapy to become pregnant at rates similar to women not diagnosed with breast cancer who underwent in vitro fertilization.
The research was published online on June 22, 2015 by the Journal of Clinical Oncology. Read the abstract of “Fertility Preservation Success Subsequent to Concurrent Aromatase Inhibitor Treatment and Ovarian Stimulation in Women With Breast Cancer.”
The study involved 131 women younger than 45 years who had been diagnosed with early-stage breast cancer (stage I through stage III):
- 34% of the women were diagnosed with hormone-receptor-positive disease
- 24% were diagnosed with HER2-positive disease
- 18% of the women had an abnormal BRCA1 or BRCA2 gene
- 85% of the women ended up being treated with chemotherapy after breast cancer surgery
- 57% of the women ended up taking tamoxifen after breast cancer surgery
Harvesting mature eggs from a woman’s ovaries before she starts breast cancer treatment is one way to preserve fertility. Without fertility drugs, only one or two eggs, at most, per cycle will be harvested. With fertility drugs, as many as eight to 10 mature eggs can be released and harvested. But using traditional fertility drugs greatly increases the amount of estrogen in the body, and that may fuel the growth of hormone-receptor-positive breast cancer cells.
To protect the women in the study from the risks of higher estrogen levels, the researchers created a special combination of medicines to stimulate egg production. The new combination uses the aromatase inhibitor medicine Femara (chemical name: letrozole) and follicle-stimulating hormone (FSH) to stimulate the ovaries to produce more eggs. An early study showed that this new combination worked just as well as traditional fertility drug combinations.
The women received the Femara/FSH combination and when their eggs were mature, they were removed from the women during a short outpatient surgery and then fertilized in a test tube with sperm from a partner or donor. This is in vitro fertilization. The fertilized eggs grew briefly into tiny embryos and were then frozen. Freezing embryos or eggs is called cryopreservation.
Of the 131 women in the study, 33 women returned to the clinic to have a frozen embryo transferred into their bodies or into a surrogate carrier.
The women who used a surrogate carrier did so for one of two reasons:
- they were taking tamoxifen, which can damage developing embryos
- they were concerned about the safety of pregnancy
Overall, the 33 women underwent 40 embryo transfer attempts:
- 18 women had the embryos transferred into their own bodies
- 22 women had the embryos transferred into a surrogate carrier
About half the embryo transfers were done more than 5 years after the embryos were frozen and about half were done less than 5 years after the embryos were frozen.
The women were an average age of 41.5 when the embryo transfers were done.
The embryo transfers resulted in 18 pregnancies and 25 babies delivered:
- seven of the 18 pregnancies (38.8%) produced twins
- there were no birth defects reported in the children
- 17 of the 33 women attempting to have children had at least one child
- 14 of the 25 babies were born to surrogate carriers
The researchers reported that the overall live birth rate per embryo transfer was similar to the U.S. national average among infertile women of about the same age who hadn’t been diagnosed with breast cancer who underwent in vitro fertilization embryo transfer.
“Our findings contribute to the safety track record of the [Femara] protocol and indicate that [Femara] has no detrimental effect on the [egg], the resulting embryos, or the offspring,” the researchers wrote. “Given this sustained track record, we surmise that the [Femara] protocol should be used more commonly to offer the possibility of fertility preservation by established cryopreservation methods in women with breast cancer.”
If you’re a younger woman diagnosed with early-stage breast cancer and are concerned about preserving your fertility, this study is very encouraging. You might want to ask your doctor about the Femara/FSH fertility drug combination for egg harvesting and whether it makes for your unique situation.
If you are worried about having children after breast cancer treatment, it’s important to talk to your doctor about fertility preservation as you are planning your treatment. You also can ask for a referral to a fertility specialist for counseling before treatment begins.
For more information, visit the Breastcancer.org pages on Fertility and Pregnancy Issues During and After Breast Cancer.
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