Pregnancy and Breast Cancer
Pregnant women can, and do, develop
and therapy are
just as important in this population as in the population at large.
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.
Today about 1 out of 3,000 pregnant women is diagnosed with breast cancer.
about many hormone changes in the body. It
interrupts the normal menstrual cycle hormone levels for some time. Because of
this, women who go through pregnancy while they are young may have a slightly
lower risk of breast cancer. Women who have had no children or who had their
first pregnancy after age 30 have a slightly higher breast cancer risk.
It is helpful to conceptually divide the management of Breast Cancer during
pregnancy into 2 steps:
Making the correct diagnosis, and
Managing the pathology in an appropriate and definitive manner that is as
gentle as possible to the developing pregnancy and to the process of
Breast cancer detection 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 enlarge and become more
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 breasts become denser. The early changes caused by cancer could also
be mistaken for or hidden by the normal changes that happen with pregnancy.
It is relatively 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 abdomen 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
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
Although a new lump or abnormal imaging test result may cause concern, breast
cancer can only be diagnosed by biopsy.
During a biopsy a piece of tissue is taken from the area of concern. This is
usually done either using a long, hollow needle or through a small surgical
incision. A breast biopsy during pregnancy can usually be done on an outpatient
basis. Local anesthesia is used to numb just the involved breast area. This
causes little risk to the fetus. The biopsy can also be done under general
anesthesia (where drugs are used to put the patient into a deep sleep) if
needed, with only a very small risk to fetal well-being.
If breast cancer has been diagnosed, 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 diagnosed at a more advanced
stage. Which staging tests may be needed depends on the situation.
The fetus is not exposed to radiation with certain 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.
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
abdomen is shielded.
Other tests, such as bone scans or computed tomography (CT) scans of the
chest, abdomen, 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 fetus's exposure to radiation as much as
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, and what the patient prefers. Treating a pregnant
woman with breast cancer has the same goals as treating a non-pregnant woman:
control the local disease and keep the cancer from spreading.
If the cancer is still in the early stages (Stage I or II), the doctor will
most likely recommend that you have surgery to remove either the suspicious lump
(lumpectomy) or the affected breast (mastectomy). During the operation, the
surgeon will examine the lymph nodes to see whether any are affected and will
(usually) remove the lymph nodes where the cancer is most likely to have spread.
If it is necessary to give chemotherapy, your doctor will usually wait until
after the first trimester to reduce the chances that it will harm the baby.
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 womanís prognosis (outlook for survival).
If the cancer is more advanced (Stage III or IV), the situation can become very
complicated. If radiation is needed to treat the cancer, it can be very hard to
protect the baby. Additionally, these cancers usually require both surgery and
chemotherapy, so the risk of harming the baby is much higher. There have been
instances where the cancer is advanced to the point where any treatment is not
likely to add more than a year or two to the woman's life. In these cases,
whether or not to undergo the treatment and risk harming the baby can be an
agonizing decision for both the woman and her family.
When possible, surgery is the first line of treatment for any woman with
breast cancer, including those who are pregnant. Lumpectomy (removal of the
tumor), mastectomy (removal of the entire breast), and/or axillary lymph node
removal 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 medicines 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.
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 between
surgical options. Radiation could affect the fetus if given during the
pregnancy, so it cannot be used until after the birth. Doctors donít know how
this delay may affect a womanís risk of the cancer coming back (recurrence).
Depending on the stage of the disease, a woman may get more treatment such as
chemotherapy, radiation therapy, and/or hormone therapy after surgery (this is
called adjuvant treatment) to help lower the risk of the cancer coming back.
Chemotherapy, which is also called chemo, may be used as an additional
(adjuvant) treatment after surgery 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 trimester (the first 3 months of
pregnancy). This is because most of the fetus's internal organs develop during
the first trimester. The risk of miscarriage 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.
Until recently, it was thought that all chemo drugs would harm the fetus. But
studies have shown that certain chemo drugs used during the 2nd and 3rd
trimesters (the 4th to 9th months of pregnancy) do not raise the risk of
defects or stillbirths. But we still do not know whether these children have any
When a pregnant woman with early breast cancer needs adjuvant chemo after
surgery it is usually delayed until at least the 2nd 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
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 in cancer treatment 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 effect how well the radiation
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 should not be started until after the woman has given birth.
All women should be encouraged to practice breast self-examination in
pregnancy and during lactation.
There is good evidence that the risk for premenopausal breast cancer is
reduced with lactation. This protective effect seems to be best for women who
had extended periods of
during their lifetime. Women with familial risks could potentially benefit
most from breastfeeding. Since breast milk is the ideal nutrient for the
newborn, and since breastfeeding is a modifiable risk factor, all women should
be encouraged to breastfeed their children.
Once breast cancer is diagnosed, a multidisciplinary approach should be
taken. This includes the obstetrician, surgeons, medical and radiation
oncologists, and breast cancer counsellors.
In early pregnancy, the patient should be counseled regarding the effect
of proposed therapy on the fetus and on overall maternal prognosis.
Termination of pregnancy should be discussed, but the patient should be
counseled that prognosis is not altered by termination of pregnancy. Women
should be advised that premature menopause may result from breast cancer
treatments, especially if chemotherapy is given to patients who are past the
age of 30.
Prior to attempting pregnancy, a breast cancer survivor should be referred
for a full oncologic evaluation.
Dated 01 October 2014