Having breast cancer during pregnancy is
very rare. But more and more women are choosing to have children later in life,
and the risk of breast cancer goes up as women get older. Because of this,
doctors expect there will be more cases of breast cancer during pregnancy in
the future.
Breast cancer is found in about 1 in
every 3,000 pregnant women. Breast cancer is the most common type of cancer
found during pregnancy, while breastfeeding, or within the first year of
delivery. You may hear this called gestational breast cancer or
pregnancy-associated breast cancer (PABC). The special concerns of breast
cancer during pregnancy are reviewed here.
Finding
breast cancer during pregnancy
When a pregnant woman develops breast
cancer, it’s often diagnosed at a later stage than it would be if the woman
were not pregnant. It’s also more likely to have spread to the lymph nodes.
This is partly because hormone changes during pregnancy. Pregnancy stops
monthly menstrual cycles and the levels of estrogen and progesterone go up.
Prolactin, a hormone that tells the breasts to prepare for nursing, also goes
up during pregnancy. These hormone changes cause the breasts to change. They
may become larger, lumpy, and tender. This can make it harder for the woman or
her doctor to notice a lump caused by cancer until it gets quite large.
Another reason it may be hard to find
breast cancers early during pregnancy is that screening for breast cancer is
often delayed until after the pregnancy is over. Pregnancy and breast feeding
can also make breast tissue denser. This can make it harder to see an early
cancer on a mammogram. Also, the early changes caused by cancer can be easily
mistaken for the normal changes that happen with pregnancy. Delayed diagnosis
remains one of the biggest problems with breast cancer in pregnancy.
If you find a lump or notice any changes
in your breasts, take it seriously. If your doctor doesn’t want to check it out
with tests such as a mammogram, ask about other kinds of imaging tests such as
ultrasound or MRI. You may need to get a second opinion. Any suspicious breast
changes should be checked out or even biopsied before assuming they are a
normal response to pregnancy.
Mammograms can find most breast cancers
that start when a woman is pregnant, and it’s thought to be fairly safe to have
a mammogram during pregnancy. The amount of radiation needed for a mammogram is
small. And the radiation is focused on the breasts, so that most of it does not
reach other parts of the body. For extra protection, a lead shield is placed
over the lower part of the belly to stop radiation from reaching the womb.
Still, scientists can’t be certain about the effects of even a very small dose
of radiation on an unborn baby.
Even during pregnancy, early detection
is an important part of breast health. Talk to your doctor or nurse about
breast exams and the best time for your next mammogram. As always, if you find
a lump or change in your breasts, tell your doctor or nurse right away.
Breast
cancer diagnosis and staging during pregnancy
Breast
biopsy during pregnancy
A new lump or abnormal imaging test
result may cause concern, but a biopsy is needed to find out if a breast change
is cancer. During a biopsy a piece of tissue is taken from the area of concern.
Breast biopsies are most often done using a needle. This is usually done as an
outpatient procedure (even on a pregnant woman). The doctor uses medicine to
numb just the area of the breast involved in the biopsy. This causes little
risk to the fetus.
If a needle biopsy doesn’t provide an
answer, a surgical biopsy is the next step. This means removing a piece of
tissue through a small cut (incision) in the breast. Surgical biopsies are
often done under general anesthesia (where drugs are used to put the patient
into a deep sleep), which carries a small risk to the fetus.
You can get more details on different
types of breast biopsies in our document called For Women Facing a Breast
Biopsy.
Tests
to learn the stage of the breast cancer
If breast cancer is found, other tests
may be needed to find out if cancer cells have spread within the breast or to
other parts of the body. This process is called staging. Staging is very
important for pregnant women with breast cancer because their cancers tend to
be found at a more advanced stage (the tumor is likely to be bigger and to have
spread beyond the breast). Which staging tests may be needed depends on your
case.
Keep in mind that tests like ultrasound
and magnetic resonance imaging (MRI) scans do not expose the fetus to
radiation. Overall, these tests are thought to be safe and can be used if they
are important to your care. But the contrast material (dye) sometimes used in
MRI crosses the placenta, the organ that connects the mother to the fetus. It
has been linked with fetal abnormalities in lab animals. For this reason, an
MRI with contrast dye is not recommended during pregnancy. But an MRI without
contrast can be used if needed.
Chest x-rays are sometimes needed to
help make treatment decisions. They use a small amount of radiation. They are
thought to be safe for pregnant women when the belly is shielded.
Other tests, such as PET scans, bone
scans, and computed tomography (CT) scans are more likely to expose the fetus
to radiation. These tests are not often needed, especially if the cancer is
thought to be just in the breast. For some of these tests, doctors may be able
to adjust the way the test is done to limit the amount of radiation the fetus
is exposed to if the tests musts be done.
In very few cases, the cancer has
reached the placenta (the organ that connects the mother to the fetus). This
could affect the amount of nutrition the fetus gets from the mother, but there
are no reported cases of breast cancer being transferred from the mother to the
fetus.
Breast
cancer treatment during pregnancy
If breast cancer is found during
pregnancy, the treatment recommendations depend on things such as:
The
size of the tumor
Where
the tumor is
If
the cancer has spread and if it has, how far
How
far along the pregnancy is
What
the woman prefers
Treating a pregnant woman with breast
cancer has the same goal as treating a non-pregnant woman: control the cancer
and keep it from spreading. But the extra concern of protecting a growing fetus
may make reaching these goals more complex.
Surgery for breast cancer is generally
safe in pregnancy. Other treatments for breast cancer, such as chemotherapy,
hormone therapy, targeted therapy, and radiation can harm the fetus if given
during pregnancy. Although chemotherapy seems to be safe for the fetus if given
later in pregnancy, it isn’t safe early on. If a women has breast cancer in
early pregnancy and needs chemotherapy right away, she may be asked to think
about ending the pregnancy. For some breast cancers, such as inflammatory
breast cancer, a delay in treatment would likely harm the patient.
Older studies reportedly found that
ending a pregnancy in order to have cancer treatment didn’t improve a woman’s
prognosis (outlook). (See the section “Survival rates after breast cancer
during pregnancy” for further discussion on this.) Even though there were flaws
in these studies, ending the pregnancy is no longer routinely recommended when
breast cancer is found. Still, this option may be discussed when looking at all
the treatment choices available, especially in aggressive cancers that may need
immediate treatment. Women and their families need to fully understand the
risks and benefits of all their options before making treatment decisions.
Surgery
Surgery to remove the cancer in the
breast and nearby lymph nodes is generally safe in pregnancy. This is a major
part of treatment for any woman with early breast cancer, including women who
are pregnant. For many cancers, either removing the entire breast (mastectomy)
or just the part containing the cancer (breast-conserving surgery - BCS) is an
option. Mastectomy is used more often for pregnant women with breast cancer
because women who have breast-conserving surgery need radiation therapy
afterward.
Radiation could affect the fetus if it
is given during the pregnancy, so it can’t be given until after delivery, and
delaying radiation too long could increase the chance of the cancer coming
back. Cancer that’s found in the third trimester may mean very little delay in
radiation treatments, so there would probably be no effect on outcome. And
radiation is normally given after chemotherapy (chemo), so a woman who will be
getting chemo after surgery may have little or no delay in her radiation
treatments. But cancers found early in the pregnancy may mean a longer delay in
starting radiation. These cancers often need to be treated with mastectomy.
In addition to removing the tumor in the
breast, one or more lymph nodes in the armpit also need to be removed to check
for cancer spread. One way to do this is an axillary lymph node dissection.
This removes many of the lymph nodes under the arm. Another procedure, called a
sentinel lymph node biopsy (SNLB), might be an option depending on the how far
along you are in pregnancy and your cancer stage. This procedure uses tracers
and dye to pinpoint the nodes most likely to contain cancer cells. SNLB allows
the doctor to remove fewer nodes. But there are concerns about the effects the
radioactive tracer and blue dyes that are used for SNLB might have on the
fetus. Because of these concerns, some experts recommend that SLNB only be used
later in pregnancy.
Anesthesia
Surgery for breast cancer generally
carries little risk to the fetus. But there are certain times in pregnancy when
anesthesia (the drugs used to make you sleep for surgery) may be riskier for
the fetus.
Many doctors, such as a high-risk
obstetrician, a surgeon, and an anesthesiologist will need to work together to
decide the best time during pregnancy to do surgery. If the surgery is done
later in the pregnancy, the obstetrician may be there just in case there are
any problems with the baby during surgery. Together, these doctors will decide
which drugs and techniques are the safest for both the mother and the baby.
Treatment
after surgery
Depending on the cancer’s stage, a woman
may get more treatment such as chemotherapy, radiation, and/or hormone therapy
after surgery to help lower the risk of the cancer coming back. This is called
adjuvant treatment. In some cases, this treatment can be put off until after
delivery.
More information about the kinds of
surgery used to treat breast cancer can be found in our document Breast Cancer.
Chemotherapy
Chemotherapy, which is also called
chemo, may be used along with surgery (as an adjuvant treatment) for some
earlier stages of breast cancer. It also may be used by itself for more
advanced cancers.
Chemo is not given during the first 3
months of pregnancy (the first trimester). Because most of the baby’s internal
organs develop during this time, the safety of chemo hasn’t been studied in the
first trimester. The risk of miscarriage (losing the baby) is also the greatest
during this time.
For many years, it was thought that all
chemo would harm an unborn baby no matter when it was given. But studies have
shown that certain chemo drugs used during the second and third trimesters
(months 4 through 9 of pregnancy) don’t raise the risk of birth defects,
stillbirths, or health problems shortly after birth, though they may increase
the risk of early delivery. Researchers still don’t know if these children will
have any long-term effects.
When a pregnant woman with early breast
cancer needs chemo after surgery (adjuvant chemo), it’s usually delayed until
at least the second trimester. If a woman is already in her third trimester
when the cancer is found, the chemo may be delayed until after birth. The birth
may be induced (brought on) a few weeks early in some cases. These same
treatment plans may also be used for women with more advanced cancer.
Chemo should not be given after 35 weeks
of pregnancy or within 3 weeks of delivery because it can lower the mother’s
blood counts. This could cause bleeding and increase the chances of infection
during birth. Holding off on chemo for the last few weeks before delivery
allows the mother’s blood counts to return to normal before childbirth.
Radiation
therapy
Radiation therapy to the breast is often
used after breast-conserving surgeries (lumpectomy or partial mastectomy) to
help reduce the risk of the cancer coming back. The high doses of radiation
used for this can harm the fetus any time during pregnancy. It may cause
miscarriage, birth defects, slow fetal growth, or a higher risk of childhood
cancer. Because of this, doctors don’t use radiation treatment during
pregnancy.
Pregnant women who choose lumpectomy or
partial mastectomy may be able to have surgery during pregnancy and then wait
until after the baby is born to get radiation therapy. But this treatment
approach has not been well-studied. Waiting too long to start radiation can
increase the chance of the cancer coming back.
Hormone
therapy
Hormone therapy is often used as
adjuvant treatment after surgery or as treatment for advanced breast cancer in
women with hormone receptor positive breast cancer. Drugs used for hormone
therapy of early breast cancer include tamoxifen, anastrozole, letrozole, and
exemestane. Other hormone therapy drug can be used for advanced breast cancer.
Hormone therapy should not be used
during pregnancy because it can affect the fetus. It should be delayed until
after the woman has given birth.
Targeted
therapy
Drugs that target HER2, like trastuzumab
(Herceptin®), pertuzumab (Perjeta®), ado-trastuzumab emtansine (Kadcyla™) and
lapatinib (Tykerb®), are an important part of the treatment of HER2-positive
breast cancers in women who aren’t pregnant. Trastuzumab is used as a part of
adjuvant treatment after surgery, pertuzumab can be used with trastuzumab
before surgery, and all of these drugs can be useful in treating advanced
cancer. But based on animal studies and reports of women who were treated
during pregnancy, none of these drugs are considered safe for the fetus if
taken during pregnancy.
Everolimus (Afinitor®) and bevacizumab
(Avastin®) are also targeted drugs that can be used to treat advanced breast
cancer. Again, neither of these drugs is safe to use during pregnancy.
Breastfeeding
during cancer treatment
Most doctors recommend that women who
have just had babies and are about to be treated for breast cancer should stop
(or not start) breastfeeding.
If surgery is planned, stopping
breastfeeding will help reduce blood flow to the breasts and make them smaller.
This can help with the operation. It also helps reduce the risk of infection in
the breast and can help avoid having breast milk collect in biopsy or surgery
areas.
Many chemo, hormone, and targeted
therapy drugs can enter breast milk and be passed on to the baby. Breastfeeding
isn’t recommended if the mother is getting chemo, hormone, or targeted therapy.
If you have questions, such as when it
might be safe to start breastfeeding, be sure to talk with your health care
team. If you plan to start back after you’ve stopped breastfeeding for a while,
you will want to plan ahead. You may need extra help from breastfeeding
experts.
Pulling
all the treatment plans together
The hardest part of treatment is when
there is a conflict between the best known treatment for the mother and the
well-being of the fetus. If you are pregnant and have breast cancer, you may
have hard choices to make—be sure you know all your options and get expert
help. Your obstetrician will need to work with your surgeon, oncologist,
radiation oncologist, and others involved in your care. A counselor or
psychologist should also be part of your health care team, to help give you the
emotional support you need.
If you would like more information on
breast cancer and its treatment, please read our document called Breast Cancer.
Survival
rates after breast cancer during pregnancy
Pregnancy can make it harder to find,
diagnose, and treat breast cancer. Most studies have found that the outcomes
among pregnant and non-pregnant women with breast cancer are about the same for
cancers found at the same stage, but not all studies agree. A 2013 study looked
at more than 300 women diagnosed during pregnancy. During the 5-year follow-up,
researchers reported comparable survival in women at the same stage whose
breast cancer was found when they weren’t pregnant. Disease-free survival
tended to be slightly shorter in the pregnant women.
Some doctors believe that ending the
pregnancy may help slow the course of more advanced breast cancers, and they
may recommend that for some women with advanced breast cancer. It’s hard to do
research in this area, and good, unbiased studies don’t exist. Ending the
pregnancy makes treatment simpler, but older studies that looked at pregnant
women have reportedly not found that ending the pregnancy improves a woman’s
overall survival or cancer outcome. Of note, there were some flaws that could
have biased the outcomes of these studies. For example, the women who had more
advanced disease were more likely to end their pregnancies. More recent studies
on this can’t be found in the available medical literature, and it’s hard to know
if outcomes would be different with more modern treatments.
Studies have not shown that the
treatment delays, sometimes needed during pregnancy, have an effect on breast
cancer outcome either. But this, too, has proven to be a difficult area to
study. Finally, there are no reports showing that breast cancer itself can harm
the baby.
