Pregnancy-Associated Breast Cancer

Pregnancy-associated breast cancer (PABC) is diagnosed during pregnancy and up to a year or more after having your baby. It’s uncommon, occurring in about 1 in 3,000 pregnancies in the U.S. Most women are diagnosed in their 30s.

Learning you have cancer while you’re pregnant can turn an already emotional time into a frightening one. But it’s important to know that there are treatments available, both during and after pregnancy. Most women go on to deliver healthy babies.

Your care team will explain the best treatments available. They’ll explain how to time them to keep you and the fetus safe. They’ll give you the information you need to make decisions about your health and the health of your pregnancy.

Symptoms of pregnancy-associated breast cancer

Signs of breast cancer during and after pregnancy are the same as those in breast cancer, in general. They include:

• A new lump in your breast or under your armpit
• A nipple that’s turned inward
• Discharge from your nipple (may be clear, whitish or bloody)
• Skin changes, like thickened or scaly skin, red or darkened areas, or pitting (resembling the skin of an orange)

It can be hard to detect these symptoms, though, because changing breast tissue is a normal part of pregnancy. These changes help your body prepare to nurse a newborn. Your breasts may get larger and feel lumpy. The tissue may become denser.

This is why it’s important to do breast self-exams during and after pregnancy. Let your pregnancy care provider know if you’re concerned that a change in your breast is abnormal. 

Pregnancy-associated breast cancer causes

Breast cancer happens when a healthy cell changes (mutates) and becomes a cancer cell. The cell makes copies that form a mass, or tumor.

Experts have different ideas about the factors that may lead to breast cancer during pregnancy. It’s possible that changing hormone levels or breast tissue may factor in. Changes in your immune system that support a healthy pregnancy may also play a role.

More research is needed to understand the connections.

How doctors diagnose this condition

Healthcare providers do clinical breast exams as part of routine prenatal and postnatal care. If they find a lump that gives them pause, you may need a:

• Breast ultrasound: This is the best first test if your provider finds a lump. Ultrasounds can show if there are masses in breast tissue. They’re completely safe for both you and the fetus.
• Mammogram: Mammograms can also show signs of cancer in your breast. They give off such low doses of radiation that they’re considered low-risk for radiation exposure. Still, your provider will place a shield on your belly as an extra safeguard to protect the fetus.
• Breast biopsy: Your provider will remove a sample of the tumor to test for cancer cells. They’ll check for certain proteins on the cells to learn the type of breast cancer.

Staging PABC

Cancer staging allows healthcare providers to tell how advanced cancer is. They use imaging to look for things like whether the cancer’s spread. The staging system for pregnancy-associated breast cancer is the same as with breast cancer, in general. Both early-stage and late-stage cancers are treatable. Your team will explain what this may look like for you.

Tests that may be a part of cancer staging include:

• A chest X-ray with a protective shield over your belly to check for cancer in your lungs
• An X-ray of the bones in your arms and legs with a protective shield over your belly
• An MRI without contrast to check for cancer spread in your spine
• An ultrasound to check for spots in your liver

Your provider will take steps to protect the fetus during these procedures. Safety measures include using a shield to block radiation. They’ll avoid using certain dyes (contrasts) during MRI or CT.

How is it treated?

You’ll work with a team of specialists who will advise you on treatments that fight cancer while protecting your pregnancy. Treatment will take into account:

• Cancer type and stage
• The timing of your pregnancy
• Your preferences

Breast cancer treatment in pregnancy generally tries to mirror breast cancer treatment in those who aren’t pregnant. The goal is to time treatment safely during pregnancy. Many people think this means delaying treatment until after the baby arrives. But many treatments are safe during pregnancy, depending on when you receive them. For others, it may be best to wait until after you deliver or breastfeed your baby.

Surgery

Surgery is an important part of treatment for PABC. You may have a lumpectomy to remove the lump, but keep your breast. You’ll likely need radiation therapy afterward to kill any remaining cancer cells. But radiation needs to be done after delivery, so this will depend on where you are in your pregnancy. Or you may have a mastectomy to remove your entire breast. With either option, you may choose to have breast reconstructive surgery.

The best option often depends on the timing of your diagnosis.

Radiation therapy

Radiation therapy is a common breast cancer treatment. But healthcare providers don’t recommend it during pregnancy because it may pose risks to the fetus.

If you get a lumpectomy in your second or third trimester, your provider may recommend radiation after your baby is born. But the timing is important. Waiting too long to have radiation after surgery may give cancer cells that are hiding time to grow back.

Chemotherapy

Your provider may recommend chemotherapy before or after surgery to fight cancer throughout your body and keep the cancer from coming back. This treatment poses health risks for the fetus in the first trimester. But many chemotherapy drugs are considered safe or low risk in the second and third trimesters. In some cases, your provider may wait to start chemotherapy until after your baby’s born.

Your provider will likely stop chemotherapy treatment about three weeks before delivery. This is because chemo reduces your blood cell counts. This can increase your bleeding risk and your chance of developing infections. Your baby’s blood cell counts could also be affected.

Other systemic treatments

Hormone therapy and targeted therapy are important treatments for some types of breast cancer. But they may pose risks to the fetus. Your provider will recommend delaying these treatments until after delivery. 

Is it safe to breastfeed after treatment?

Many can safely breastfeed after completing PABC treatment, usually using the non-affected breast.

But it’s not safe if you’re getting chemotherapy, targeted therapy or hormone therapy. This is because the drugs can travel through breast milk. With chemotherapy, it’s important that your last dose is at least three to four weeks before you start breastfeeding.

Talk to your care team so that you understand your options when it comes to breastfeeding. For example, some people decide to delay these treatments, when possible, until after the first two weeks of delivery. That way, the baby can get the colostrum from your breast milk to support their immune system. 

When should I see my healthcare provider?

Let your healthcare provider know if you have a new lump in your breast that’s been there for more than two weeks. Again, it’s important not to panic because breast changes are a normal part of pregnancy. Your provider can let you know if you need testing to be sure. 

What can I expect if I have this condition?

Your prognosis (outlook) depends more on the cancer type and stage than whether you were diagnosed during pregnancy. It’s true that treatment delays can lead to worse outcomes. But your care team will do their best to time your treatment so that it’s effective for you — and safe for the fetus.

As with any pregnancy, your providers will monitor the fetus closely. They’ll make sure you’re getting the right nutrition, exercise and sleep for a healthy pregnancy.

Most women with pregnancy-associated breast cancer will have healthy babies.

​How soon can I try for another baby?

Your care team may suggest that you wait two years after treatment before trying for another baby.

This gives your healthcare providers time to watch for cancer recurrence and provide treatment.

Some treatments, like hormone therapy, are given for five to ten years. Having a baby during this timeframe may be possible, but you’d need to discuss this with your provider. You’d have to be off hormone therapy for this period. It’s ultimately best for your care team to guide this discussion and see if that’s an option for you.

Is there anything I can do to feel better?

One of the best things you can do is get to know your care team. Your experience will depend on the decisions they make together. It’s important that you’re comfortable enough with them to ask questions and voice concerns. Remember that you’re the most important decision-maker in this process. Assemble a team whose guidance you trust and who will support your wishes during pregnancy.

What is the most common breast cancer associated with pregnancy?

Most are triple-negative or HER2-positive breast cancers. These types are less common in non-pregnancy-related breast cancers. Researchers are studying the reasons for the difference.