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Sidney Kimmel Cancer Center / Centers & Clinics

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Pregnancy-Related Breast Cancer

Pregnancy-Related Breast Cancer Diagnosis

Pregnancy-related breast cancer is rare, but about one in 3000 pregnant women are diagnosed. Many women have gone on to have healthy babies and live healthy lives after a diagnosis of breast cancer; in fact, research has shown that pregnant women diagnosed with breast cancer do as well or even better than non-pregnant women.  Any breast cancer that is found during pregnancy, while breastfeeding, or within a year following delivery of a baby is considered a pregnancy-related breast cancer.

Because of the changes in the breast that occur during pregnancy and breastfeeding, breast cancer can be difficult to diagnose.  For this reason, pregnancy-related breast tumors tend to be larger and of a higher stage than those in non-pregnant women.   Still, many diagnostic procedures and treatments are safe for pregnant women and their babies.

Pregnancy-Related Breast Cancer Staging and Treatment

Treatment for a breast cancer that is found during pregnancy will depend on the stage of the tumor and on how far along you are in your pregnancy.  Most pregnancy-related breast cancers are treated with some combination of local therapy and systemic therapy, though treatment may be somewhat different, or done in a different sequence, than if you were not pregnant.

Local therapy is aimed at preventing the cancer from coming back in the breast. In general, local therapy includes either breast conservation surgery (lumpectomy with radiation), or mastectomy.  Radiation is not recommended during pregnancy, but sometimes lumpectomy can be done during pregnancy and radiation started after the baby is born.

Systemic therapy is used to prevent the disease from coming back or spreading to another part of the body.  This may include endocrine (hormone) therapy, chemotherapy, and therapy that targets the HER2 protein.  Often, different types of treatment are used together to achieve the best result.

During the first trimester, chemotherapy can cause birth defects or loss of the baby, and for this reason is not given during this time.  Some chemotherapy can be safely given in the second and third trimesters, however, without harm to the baby.

  • Chemotherapy given before surgery (neoadjuvant therapy) may be recommended during pregnancy.
  • If your tumor is estrogen- or progesterone-positive, your doctor may recommend endocrine (hormone) therapy.  Endocrine therapy is not recommended during pregnancy, but may be started after delivery.
  • If your tumor is HER2 positive (expressing the HER2 protein), therapies that target HER2 may also be part of the treatment plan and will be started after delivery.
  • Your doctors may discuss with you the possibility of delivering your baby early, so that treatment can be started without delay.

Breastfeeding is affected by the treatment for breast cancer.  Surgery on a lactating breast can be more complicated; chemotherapy and hormonal therapy may cross into breast milk and are often not safe for the baby.  It may be recommended that you stop or delay breastfeeding. A lactation specialist may help answer your questions about breastfeeding now and in the future.

Your oncology team will work closely with maternal-fetal medicine specialists to recommend a treatment plan based on the features of the tumor (type of cells, tumor grade, hormone receptor status, and HER2 status) and the stage of the disease (tumor size and node status).