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Very few pregnant women are diagnosed with breast cancer. But
because more women are choosing to have children later in life, and
because the risk of breast cancer increases as women age, there may be
more cases in the future. For instance, only 1 in 50 breast cancers are
found in woman under 35, but about 1 in 9 breast cancers are found in
women aged 35 to 44. Women 45 and older have an even higher risk.
Estimates are that about 1 out of 3,000 pregnant women is
diagnosed with breast cancer.
Breast cancer risk
What is cancer?
Normal body cells grow, divide, and die in an orderly fashion.
During the early years of a person's life, normal cells divide more
quickly until the person becomes an adult. After that, cells in most
parts of the body divide only to replace worn-out or dying cells and to
repair injuries.
Because cancer cells keep on growing and dividing, they are
different from normal cells. Instead of dying, they outlive normal
cells and keep making new, abnormal cells. Hormones like estrogen help
normal breast cells grow and divide, but can also promote the growth of
breast cancer cells.
How your menstrual cycles affect breast
cancer risk
Women who are exposed to higher levels of estrogen over longer
periods of time seem to have a slightly higher risk for breast cancer.
This includes women who had more menstrual periods, such as those who
started menstruating before age 12 or who went through menopause after
age 55.
How pregnancy affects breast cancer risk
later in life
Pregnancy causes many hormone changes in the body. For one
thing,
pregnancy stops the monthly menstrual cycles and shifts the hormone
balance toward progesterone rather than estrogen. This is why women who
go through a pregnancy while they are young may have a slightly lower
risk of breast cancer later on. Women who have had no children or who
had their first pregnancy after age 30 have a slightly higher breast
cancer risk later in life.
How breast-feeding affects breast cancer
risk
Some studies have suggested that breast-feeding may slightly
lower
breast cancer risk. This is more likely if breast-feeding is continued
for 1½ to 2 years or if many children are breast-fed. The
reason
for this may be that both pregnancy and breast-feeding reduce a woman's
total number of lifetime menstrual cycles. But new information suggests
that breast-feeding may also affect the level of another hormone,
called prolactin.
A 2008 study showed that women who breast-fed a baby
for a year or more had lower prolactin levels for the rest their lives,
whether or not they ever breast-fed again. This may also help lower
breast cancer risk later on. More research is needed to look more
deeply into the effects of breast-feeding.
Finding breast cancer during pregnancy
When a pregnant woman develops breast cancer, it is often
diagnosed
at a later stage than it is in women who are not pregnant. This is
because during pregnancy, hormone changes cause a woman's breasts to
get larger, tender, and lumpy. This can make it harder for you or your
doctor to find a lump in your breasts. Mammograms are also harder for
doctors to read during pregnancy because the breast tissue becomes
denser. The early changes caused by cancer could be mistaken for or
hidden by the normal changes that happen with pregnancy.
It is 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 breast. 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
small dose of radiation on an unborn baby. If your doctor does not
believe you need to have your mammogram right away, it may be best to
wait. Other imaging tests that do not use radiation, such as breast
ultrasound, may be used instead. These are thought to be safe
alternatives to mammograms during pregnancy.
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 -- especially if you are age 40 or
older, or if you or your doctor notices a change in how your breasts
look or feel. As always, if you find any lump or change in your
breasts, tell your doctor or nurse right away.
Breast cancer diagnosis and staging during
pregnancy
Biopsy
A new lump or abnormal imaging test result may cause concern,
but a
biopsy is needed to find out if it is breast cancer. During a biopsy a
piece of tissue is taken from the area the doctors are concerned about.
This is usually done either using a long, hollow needle or through a
small surgical incision (cut). A breast biopsy during pregnancy can
usually be done without being admitted to the hospital. The doctor uses
medicine to numb just the area of the breast involved in the biopsy.
This causes little risk to the fetus. But the biopsy can be done under
general anesthesia (where drugs are used to put the patient into a deep
sleep) if needed, with only a small risk to the fetus.
You can get more detailed information on different types of
breast biopsies in our document, For Women Facing a Breast Biopsy.
Other tests
If breast cancer has been 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 tests are very
important for pregnant women with breast cancer because their cancers
tend to be found at a more advanced stage. Which staging tests may be
needed depends on your case.
Keep in mind that the fetus is not exposed to radiation with
tests
such as ultrasound and magnetic resonance imaging (MRI) scans. Overall,
these tests are thought to be safe and can be used if they are
important to your care. But, the contrast
material or 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 that uses contrast dye is not recommended
during pregnancy. But an MRI without contrast does not involve
radiation and can be used if needed.
Chest x-rays, sometimes needed to help make treatment
decisions, use
a small amount of radiation. They are thought to be safe for pregnant
women when the belly is shielded.
Other tests, such as bone scans or computed tomography (CT)
scans of
the chest, abdomen (belly), or pelvis, 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. In rare cases when these
scans are needed, doctors can adjust the way the test is done to limit
the amount of radiation the fetus is exposed to.
There are no reported cases of breast cancer being transferred
from
the mother to the fetus. 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.
Breast cancer treatment during pregnancy
If breast cancer is found during pregnancy, the type and
timing of treatment depends on many things, such as:
- the size of the tumor
- where the tumor is
- how far along the pregnancy is
- what the woman prefers
Treating a pregnant woman with breast cancer has the same
goals as
treating a non-pregnant woman: control the cancer in the place where it
started, and keep it from spreading. But protecting a growing embryo or
fetus may make reaching these goals more complex.
If you would like more information on breast cancer
treatments, look at our document, Breast Cancer.
If a pregnant woman needs chemotherapy, hormone therapy, or
radiation therapy to treat breast cancer, she may be asked to think
about ending the pregnancy. This is because these treatments may harm
the fetus. It is easier to treat a woman who is not pregnant because
there is no fear of harming the fetus. But no studies have proven that
ending a pregnancy in order to have cancer treatment improves the
woman's prognosis (outlook). These issues are discussed in more detail
in sections below.
Surgery
When possible, surgery is the first line of treatment for any
woman
with breast cancer, including those who are pregnant. Removing the
tumor (lumpectomy) or the entire breast (mastectomy), and/or taking out
the lymph nodes under the arm carry 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 the obstetrician, surgeon, and the anesthesiologist will need to
work together to decide the best time during pregnancy to do the
surgery. They can also decide which drugs and techniques are the safest
for both the mother and the baby.
Mastectomy can often be used as the first treatment for early
stage
cancers. 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, since it's used along with the main
treatment (surgery).
Women who have breast-saving surgery, like lumpectomy, often
need
radiation therapy afterward to reduce the chance that the cancer will
come back. The need for radiation is an important issue for pregnant
women when choosing which surgery to have. Radiation could affect the
fetus if given during the pregnancy, so it is not used until after the
birth. Doctors don't know how this delay may affect a woman's risk of
the cancer coming back (recurrence). Cancer found in the 3rd trimester
may involve very little delay in radiation treatments, so there would
likely be no effect on outcome. And a woman who will be getting
chemotherapy before radiation may have little or no delay in her
radiation treatments. But cancers found early in the pregnancy may mean
more delay in radiation. Treatment must always be considered on a case
by case basis.
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 usually is not given during the first 3 months of
pregnancy
(which is called the first trimester).
This is because most of the
fetus's internal organs develop during the first trimester. The risk of
miscarriage
(losing the baby) is also the greatest during the first
trimester. The safety of chemo during this time has not been studied
because of concerns about damage to the fetus.
It was once thought that all chemo drugs would harm the fetus.
But
studies have shown that certain chemo drugs used during the second and
third trimesters (the fourth through ninth months of pregnancy) do not
raise the risk of birth defects or stillbirths. Researchers still do
not know whether these children will have any long-term effects.
When a pregnant woman with early breast cancer needs adjuvant
chemo
after surgery, it is usually delayed until at least the second
trimester. For a woman already in her 3rd trimester when the cancer is
found, adjuvant chemo may be delayed until after birth. The birth may
be induced
(brought on) a few weeks early in these cases. Depending on
the extent of the cancer, these same treatment plans may also be used
for women whose disease is more advanced.
Chemo should not be given 3 to 4 weeks before delivery. This
is
because one side effect of chemo is that it lowers 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 levels
before childbirth.
Radiation therapy
Radiation therapy to the breast is often used after
breast-conserving surgeries (lumpectomy or partial mastectomy) to
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, or slow fetal growth, so doctors do
not recommend its use during pregnancy.
Pregnant women who choose lumpectomy or partial mastectomy can
usually have surgery during the pregnancy and wait until after the baby
is born to have radiation therapy. But this treatment approach has not
been well-studied in pregnant women. And it is not known if the changes
that take place in the breasts during pregnancy and the time delay
might affect how well the radiation works.
Hormone
therapy
Hormone therapy, such as treatment with tamoxifen, may be used
as
adjuvant treatment after surgery or as treatment for advanced cancer.
Its use in pregnant women has not been well-studied, so its effects are
not known. Most infants born to women taking tamoxifen are normal. But
there have been reports of head and face birth defects in a few babies
born to women who became pregnant while taking tamoxifen. More study in
this area is needed.
At this time it is recommended that hormone therapy for breast
cancer treatment not be started until after the woman has given birth.
Breast-feeding 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)
breast-feeding.
If surgery is planned, stopping breast-feeding 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 and hormone therapy drugs can enter breast milk and
could
be passed on to the baby. So, if the mother is getting chemo or hormone
therapy she shouldn't breast-feed her baby.
If you have specific questions, such as when it might be safe
to
start breast-feeding, be sure to talk with your health care team. If
you plan to start back after you've stopped breast feeding for awhile,
you will want to plan ahead. You may need extra help from breast
feeding 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. A woman who is found to have breast cancer during a pregnancy
may have hard choices to make, and needs to have expert help. Her
obstetrician will need to work with her surgeon, her oncologist, her
radiation oncologist, and others. Through all this, the woman with
breast cancer will need emotional support, so a counselor or
psychologist should also be part of her care team.
Effect of pregnancy on survival after breast
cancer
Pregnancy before breast cancer
Some studies have found that women who were diagnosed with
breast
cancer within 2 years after giving birth did not do as well as other
women with breast cancer, but other studies have not found such a
difference. More research is needed in this area.
Pregnancy during breast cancer
Pregnancy may make it harder to find and diagnose breast
cancer. But
most studies have found that the outcome among pregnant and
non-pregnant women with breast cancer is about the same for cancers
found at the same stage. For example, a study at Memorial
Sloan-Kettering Cancer Center showed that pregnant women who had a
mastectomy did no worse than women who were not pregnant and had a
mastectomy. Survival rates after 5 and 10 years were almost the same in
these 2 groups. So pregnancy and the breast changes it causes did not
worsen the mother's chances of surviving breast cancer.
Some doctors believe that ending the pregnancy may help slow
the
course of more advanced breast cancers, and they may recommend an
abortion in these cases. It has been hard to prove whether this
improves the women's outcomes. It is hard to do research in this area
and very few good studies have been done. The studies that have been
done have not shown that ending the pregnancy improves a woman's
survival or cancer outcome.
Studies have not shown that the treatment delays sometimes
needed
during pregnancy have an effect on breast cancer outcome. But this,
too, has proven to be a difficult area to study.
Pregnancy after breast cancer treatment
Some treatments for breast cancer, such as certain chemo
drugs, may
affect a woman's ability to have a baby (fertility). Still, many women
are able to become pregnant after treatment. Women concerned about
their fertility should talk to their doctors about this before starting
breast cancer treatment.
Doctors are not sure if women who have had breast cancer in
the past
increase their risk of the cancer coming back by becoming pregnant. A
few studies have been done on this. Most have found that pregnancy does
not increase the risk of the cancer coming back after successful
treatment of breast cancer.
But doctors know there is a clear link between estrogen levels
and
growth of breast cancer cells. Because of this link, many doctors
advise breast cancer survivors to wait at least 2 years after treatment
before trying to get pregnant. This would give them the chance to find
any early return of the cancer, which could affect a woman's decision
to become pregnant later on. Still, this advice is not based on data
from any clinical trials. Each woman's decision is based on many
things, such as her age, her desire for more pregnancies, her risk of
an early relapse, and the potential effect estrogen may have on her
risk of a breast cancer coming back.
Women taking hormone therapy, such as tamoxifen, should talk
with
their doctors before trying to become pregnant. These drugs could
affect a growing fetus (see the section, "Hormone
therapy").
There is no proof that a woman's past breast cancer has any
effect
on her baby. But chemotherapy for breast cancer can cause some damage
to the ovaries. Treatment can also cause women to delay trying to get
pregnant. These factors together often mean that a woman has less of a
chance of getting pregnant after breast cancer treatment.
All women who have had breast cancer and are thinking about
having
children should talk with their doctors about how treatment can affect
their chances for another pregnancy. They will also want to know their
risk of cancer coming back. In many cases, counseling can help women
sort through the choices that come with surviving breast cancer and
planning a pregnancy.
Additional resources
More information from your American Cancer
Society
We have listed some related information that may also be
helpful to
you. These materials may be ordered from our toll-free number,
1-800-227-2345.
National organizations and Web sites*
Along with the American Cancer Society, other sources of
information and support include:
Breast Cancer
Network of Strength
Toll-free number: 1-800-221-2141
Web site: www.networkofstrength.org
Patients and survivors may be matched with someone who has had the same
diagnosis and is the same age. Partners of breast cancer patients may
also get support from others
National Cancer
Institute
Toll-free number: 1-800-4-CANCER (1-800-422-6237)
TYY: 1-800-332-8615
Web site: www.cancer.gov
Find special information for pregnant women with breast cancer at:
www.cancer.gov/cancertopics/pdq/treatment/breast-cancer-and-pregnancy/Patient
Hope for Two:
The Pregnant With Cancer Network
Toll-free number: 1-800-743-4471
Web site: www.pregnantwithcancer.org
Phone and online support, info packet, and newsletter for pregnant
women with cancer. Also offers women who have been through it the
chance to volunteer to help others
Young Survival
Coalition
Toll-free number: 1-877-YSC-1011 (1-877-972-1011)
Web site: www.youngsurvival.org
Offers resources, support, and information to improve quality of life
for women diagnosed with breast cancer at ages 40 and under (some
Spanish materials also available)
U. S. Food and
Drug Administration Pregnancy Exposure Registries Information
Toll-free number (for certain cancer drugs only): 1-877-635-4499
Web site: www.fda.gov/ScienceResearch/SpecialTopics/WomensHealthResearch/ucm134848.htm
Allows women who have had certain cancer treatments while pregnant to
share the chemotherapy effects on their babies with other women who
need cancer treatment
*Inclusion on
this list does not imply endorsement by the American Cancer Society.
No matter who you are, we can help. Contact us anytime, day or
night, for cancer-related information and support. Call us at
1-800-227-2345
or visit www.cancer.org.
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Last Medical Review: 08/28/2009
Last Revised: 08/28/2009
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