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.
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 notrecommended 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.
Treatment of breast cancer during pregnancy
Breast cancer is diagnosed in about 1 pregnant woman out of 3,000. In general, treatment recommendations depend upon how long the woman has been pregnant.
Radiation therapy during pregnancy is known to increase the risk of birth defects, so it is not recommended for pregnant women with breast cancer. Since breast-conserving surgery (BCS) needs to be followed with radiation, BCS is only an option if radiation can be delayed until after the baby is delivered. But breast biopsy procedures and even mastectomy and lymph node removal can be done safely in pregnancy.
For a long time it was assumed that chemotherapy (chemo) was dangerous to the fetus. But several studies have found that using certain chemo drugs during the second and third trimesters (the fourth to ninth months) does not increase the risk of birth defects. Because of concern about the potential damage to the fetus, the safety of chemo during the first trimester (the first 3 months) of pregnancy has not been studied.Both hormone therapy and targeted therapy can affect the fetus and should not be started until after the baby is born.Many chemo and hormone therapy drugs can enter breast milk and could be passed on to the baby, so breastfeeding is not usually recommended during chemo, hormone, or targeted therapy.