Breast cancer associated with pregnancy occurs anywhere in the first postpartum year, during pregnancy, or anytime during lactation.
Management of pregnant women newly diagnosed with breast cancer can be complex and depends on the trimester of pregnancy and desires for breast conservation.
Most obstetricians will recommend to deliver the baby at the earliest at 34 weeks to avoid morbidity of prematurity and treatment for the breast cancer should not be delayed until delivery. Studies have shown worse survival in those patients who delayed treatment 3 to 6 months.
It is safe to administer chemotherapy during pregnancy, but the risk of congenital malformations in the first trimester can be as high as 20% so it is generally recommended to start chemotherapy in the second or third trimester. The only agents that are contraindicated are taxanes and trastuzumab.
A study published in 2006 did not show any significant short term complications for children that were exposed to fluorouracil, doxorubicin, cyclophosphamide (FAC) chemotherapy in utero. It is not safe however to administer radiation or hormone therapy during pregnancy because of risks to the fetus.
Surgery is safe in the second and third trimester and is generally avoided in the first trimester due to risk of spontaneous abortion.
Surgical options include mastectomy and breast conservation, if applicable. If a patient has lumpectomy, radiation therapy must wait until after delivery. Sentinel node biopsy has been shown to be safe during pregnancy followed by axillary node dissection if the sentinel node is tumor positive. It is generally felt that preoperative lymphoscintigraphy is safe during pregnancy, although only a few small studies have examined sentinel node biopsy in pregnant patients. Injection of blue dye to identify a sentinel node is not recommended because of the small risk of allergic reaction and uncertain affects on the fetus.
Therapeutic abortion is no longer necessary or recommended.
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Hahn KME, Johnson PH, Gordon N, et al. Treatment of pregnant breast cancer patients and outcomes of children exposed to chemotherapy in utero. Cancer. 2006;107:1219-1226.
Khera SY, Kiluk JV, Hasson DM, et al. Pregnancy-associated breast cancer patients can safely undergo lymphatic mapping. Breast J. 2008;14:250-254.
Mondi MM, Cuenca RE, Ollila DW, Stewart JH 4th, Levine EA. Sentinel lymph node biopsy during pregnancy: initial clinical experience. Ann Surg Oncol. 2007;14:218-221.