Getting pregnant after breast cancer
A diagnosis of breast cancer at a young age can carry a host of emotional complications. In addition to navigating treatment options, younger women also have to consider how some treatments may affect their fertility.
There are many different types of breast cancer and each one is treated differently with a personalized plan for each patient. Breast surgeon Kathryn Dalton, DO, said a woman’s desire to become a mother is an important consideration, but stressed that the breast cancer must come first.
“Cancer is the number one thing we have to address,” she said.
There are various treatment options, depending on the type and stage of the cancer. Radiation of the breasts, by itself is not a risk for future pregnancies but, if chemotherapy and the hormone suppressor Tamoxifen are prescribed, they can affect a woman’s chances of having a child. They also can cause birth defects, if the medications are taken during pregnancy.
In the past, breast cancer physicians worried about pregnancy after breast cancer, especially with women who had estrogen receptor-positive breast cancer, explained Dr. Dalton. Since those cancers are fueled by estrogen, the thought was that the surge of estrogen that occurs in pregnancy might put women at risk of a recurrence of cancer. But a study that was released last year put those fears to rest.
The study involved 1,207 women who were diagnosed with breast cancer that had not metastasized. Fifty-seven percent of the women had estrogen receptor-positive breast cancer and 40 percent had poor prognostic factors like large tumors or cancer that had spread to nearby lymph nodes. Over the 10 years of the study, 333 became pregnant. In a surprising twist, women with estrogen receptor-negative cancer actually had a 42 percent lower chance of dying than those who did not, although researchers don’t know exactly why.
“Based on that study, we’re not discouraging women from getting pregnant after breast cancer,” Dr. Dalton said. “But the other thing to note is when is the appropriate time to become pregnant? If breast cancer is going to recur, it most often recurs within the first two years. So traditionally we would tell women to wait two years before trying to get pregnant, because the worst thing that can happen is for a woman to have a recurrence while they are pregnant.”
Cape Cod Hospital obstetrician Tara Chute, MD, agreed.
“Patients often want to preserve the pregnancy and then we have to decide when is a safe time to deliver so that we don’t delay treatment any longer than necessary. That becomes a very difficult question to answer,” she said.
She usually recommends that patients who have had breast cancer wait at least two years and up to five years before getting pregnant to ensure their cancer doesn’t return.
“Some chemotherapy agents have lasting effects in the body for several months, so at the very least, women should wait for an appropriate window of time after chemotherapy to minimize effects on the subsequent pregnancy, Dr. Chute said.
Those with estrogen receptor-positive breast cancer are prescribed hormone suppressors for at least five and up to 10 years. Medications like tamoxifen basically cause chemical menopause, making it nearly impossible to get pregnant. It is also toxic for developing babies.
“If they are worried about infertility from chemotherapy, then egg preservation or embryo freezing would be the recommendation. Young women with breast cancer who want to get pregnant should talk to a fertility specialist at the time of their diagnosis,” Dr. Dalton said.
Brings Up Many Questions
In the study of pregnancy after breast cancer, half of the women reported wanting to have a baby afterwards, but only 10 percent actually became pregnant. It also noted that of all cancer survivors, breast cancer survivors are the least likely to have a baby after diagnosis.
Some women are so anxious to have a child, they are willing to interrupt their hormonal therapy to do so, Dr. Dalton said. There is currently no research that can verify the safety of this decision, but a new study that began in 2014 called the POSITIVE study is trying to determine whether women can safely stop hormonal therapy for a short time in order to get pregnant. The study is expected to continue until 2028, with preliminary results in 2020.
Even though breast cancer is now highly curable, Dr. Chute said a diagnosis can bring up a lot of emotions for women about their own mortality, body image or ability to breastfeed.
“It’s something that I personally, as an obstetrician, would address with them by checking how they are doing emotionally during the pregnancy,” she said.
Another thing for young breast cancer patients to consider is that they may have a higher incidence of a genetic mutation called hereditary breast and ovarian cancer syndrome. That brings other factors into consideration, Dr. Dalton said.
“The patients with hereditary breast cancer syndrome are the ones who may choose bilateral mastectomies at their time of diagnosis. It is important for them to know their babies will each have a 50 percent chance of also having the mutation, boy or girl,” she said. “But in patients where we know about the mutation before a cancer diagnosis, we can definitely do preventative things ahead of time. When that infant is born, we don’t test them until they are 18 years old and can provide informed consent. We typically don’t start high-risk screening or preventative surgery until adulthood anyways.”
One other consideration about breast cancer and pregnancy is the ability to breastfeed. Treatment options for lumpectomies preserve much more breast tissue (and the ability to breastfeed) than in years past. Many women can go on to breastfeed successfully after breast cancer, Dr. Chute said.