Diagnosis During Pregnancy
How Breast Cancer Is Found During Pregnancy
Being diagnosed with breast cancer during pregnancy is rare, but it does happen. Many people first notice something themselves, such as a new lump or a change in the breast, while others have a change detected during a clinical breast exam as part of prenatal care.
Why Diagnosis Can Be More Difficult During Pregnancy
Hormonal changes in pregnancy and the postpartum period often make breasts larger, tender, or more lumpy. These normal shifts can make it challenging for you or your clinician to feel small lumps.
Because of this, breast cancer during pregnancy, shortly after birth, or while breast feeding may sometimes be diagnosed at a later stage; not because you missed something, but because the physical changes of pregnancy can mask early signs.
Screening Mammography and Pregnancy
Screening mammograms are not routinely done during pregnancy for people at average risk because pregnancy and breastfeeding make images harder to interpret.
- For those over age 40 at average risk: Screening mammograms are usually postponed until after delivery and after breastfeeding has ended (if breastfeeding).
- For those under age 40: Screening mammograms are uncommon unless someone has a higher-than-average risk of breast cancer.
If needed, a mammogram can be performed during pregnancy. The radiation used is low, and abdominal shielding is used to protect the fetus.
What happens if a lump or change is found?
If you or your clinician notices a lump or breast change, there are diagnostic tests that are considered safe during pregnancy. Your team may recommend:
- Diagnostic mammogram (with digital breast tomosynthesis)
- Breast ultrasound
If imaging shows something concerning, a biopsy is performed to make a diagnosis and to learn the specific features of the tumor. Biopsies are safe during pregnancy.
Understanding Breast Cancer Treatment During Pregnancy
Being diagnosed with breast cancer while pregnant brings unique concerns. Cancer itself does not affect the fetus, but certain treatments can. Your doctors carefully balance effective cancer treatment with protecting your baby when planning your care.
Surgery
Breast surgery can be safely performed during pregnancy. While anesthesia crosses the placenta, it has not been shown to cause birth defects or serious pregnancy complications.
Radiation Therapy
Radiation therapy is typically needed after a lumpectomy and in some cases after a mastectomy, but radiation given during pregnancy can harm the fetus.
For those in their first trimester, a mastectomy is usually recommended to avoid radiation exposure during pregnancy. Those in their second or third trimester may choose a lumpectomy and delay radiation until after delivery. Research shows that delaying radiation in this situation does not reduce survival.
Chemotherapy
Chemotherapy is avoided during the first trimester, when the risk of miscarriage and drug-related birth defects are highest. In the second and third trimesters, some chemotherapy drugs can be given safely.
Chemotherapy is usually not given after week 35 of pregnancy or within three weeks of the due date to allow the body time to recover before delivery.
Other Drug Therapies
Immunotherapies, endocrine therapies, and HER2-targeted therapies are not used during pregnancy due to risks to the fetus.
Survival
People diagnosed with breast cancer during pregnancy have survival rates similar to those of non-pregnant individuals of the same age and stage. In some cases, pregnancy termination may be recommended or preferred.
