The authors also noted the following contraindications for breast cancer treatment during pregnancy:

1. “Gadolinium-based contrast for MRI is not recommended”

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2. “Isosulfan blue dye is contraindicated for lymphoscintigraphy as dual tracer for sentinel lymph node biopsy”

3. “Chemotherapy is contraindicated in first trimester of pregnancy and during lactation”

4. “Endocrine treatment is contraindicated during pregnancy and lactation”

  • Tamoxifen is U.S. Food and Drug Administration (FDA) pregnancy risk Category D

5. “Anti-HER2 therapy is contraindicated in pregnancy and lactation”

  • This includes trastuzumab (FDA pregnancy risk Category D), pertuzumab, and lapatinib

6. “Radiation therapy is contraindicated during pregnancy and cautioned during lactation.”

  • Exposing a fetus to radiation therapy in utero “is postulated to increase the fetus’s risk for cancer,” notably leukemia

Due to limited data regarding the safety of supportive care agents during pregnancy, they should be used “only if the potential benefit justifies the potential risk to the fetus,” Dr Anders and colleagues wrote. The FDA category for supportive care agents classify the 5HT3 antagonists — ondansetron, palonosetron, and granisetron — as pregnancy risk category B. The G-CSF agents filgrastim and pegfilgrastim, the antiemetic promethazine, and the corticosteroids methylprednisolone and dexamethasone are pregnancy risk category C.

The authors noted that while their focus is on care of the pregnant patient with breast cancer, the literature also includes the term “pregnancy-associated breast cancer,” which has been defined as “breast cancer diagnosed during a pregnancy, during lactation, or up to 1 year (or more) after delivery.”

Because breast cancer during pregnancy is so rare, “it is essential to collect patient data in international registries,” the authors concluded.


  1. Shachar SS, Gallagher K, McGuire K, et al. Multidisciplinary management of breast cancer during pregnancy. Oncologist. 2017;22(3):324-34. doi: 10.1634/theoncologist.2016-0208