For most women who are diagnosed with breast cancer while pregnant, the baby can be carried to full term according to reports published in the Feb. 11, 2012 issue of The Lancet. Breast cancer surgery can be done any time during pregnancy. Some treatments can be given while a woman is pregnant without harming the baby, while others should be avoided or delayed until after the baby is born.
Being diagnosed while pregnant doesn't happen very often, but it does happen. Estimates vary widely -- from 1 in 1,000 to 1 in 10,000 pregnancies. Because more women are having children later in life, it's likely that rates of breast cancer diagnoses during pregnancy have increased in recent decades.
Because the breasts change normally during pregnancy, small lumps that are the beginnings of cancer can be more easily missed or might be considered part of normal pregnancy-related breast tissue change. While pregnancy doesn't cause breast cancer to develop, the changes in hormones that happen during pregnancy can promote the growth of any existing breast cancer cells. This may be why earlier research found that breast cancers diagnosed in pregnant women tend to be larger and at a more advanced stage compared to breast cancers diagnosed in women the same age who aren't pregnant.
Based on a review of research on diagnosing and treating breast cancer during pregnancy, The Lancet reports conclude there are usually no good reasons to end a pregnancy early when breast cancer is diagnosed:
- Treatment while continuing the pregnancy is generally better for the baby, since premature birth creates multiple risks for the baby.
- When evaluating a pregnant woman diagnosed with breast cancer, doctors must take care to not do tests that could expose the baby to hazards, such as radiation from x-rays.
- Breast cancer surgery to remove early-stage breast cancer can be done safely any time during a pregnancy.
- Radiation therapy is risky for the baby and should be avoided when possible. Because radiation therapy is generally given after lumpectomy, mastectomy instead of lumpectomy usually is the recommended type of surgery.
- Most chemotherapy medicines used to treat breast cancer after surgery can be given during the second and third trimesters (after 14 weeks) without harming the baby; some types of chemotherapy (taxanes, for example) shouldn't be used during the pregnancy.
- Other breast cancer treatments shouldn't be used during pregnancy (but can be used after delivery), including hormonal therapies (tamoxifen and the aromatase inhibitors) and targeted therapies such as Herceptin (chemical name: trastuzumab), Avastin (chemical name: bevacizumab), and Tykerb (chemical name: lapatinib).
- For women diagnosed with similar types of breast cancer, the overall prognosis is about the same for women treated during pregnancy compared to women who aren't pregnant.
If you've been diagnosed with breast cancer while you're pregnant, you may understandably feel overwhelmed and inclined to either end the pregnancy early to get treatment started or delay any treatment until after the baby delivers. The good news is that it's very likely that you can safely give your baby all the benefits of a full-term pregnancy while getting breast cancer treatment underway as soon as possible. Ideally, you should receive care from a multidisciplinary team of specialists who can address all of your needs -- obstetrical, medical, surgical -- as well as the needs of your baby. Together with that team you can create a treatment plan based on your specific situation that is best for both you AND your baby.
The National Comprehensive Cancer Network (NCCN) is an alliance of 21 of the world's leading cancer centers. These NCCN centers collaborate on research, guidelines, and education to improve the care of people diagnosed with cancer. Both the NCCN and the American Cancer Society (ACS) offer guidance on breast cancer diagnosis and treatment during pregnancy. The conclusions in The Lancet reports are in agreement with the NCCN/ACS guidelines. You can review the ACS guidelines on breast cancer diagnosis and treatment during pregnancy at the American Cancer Society website.