Pregnancy-Associated Breast Cancer

Kathleen Logue, RNC-OB, BSN


Clin J Oncol Nurs. 2009;13(1):25-27. 

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Pregnancy-Associated Breast Cancer

Pregnancy typically is viewed as a time of health and wellness, so the possibility of being diagnosed with cancer usually is far from a pregnant woman's mind. Although uncommon, breast cancer is second to cervical cancer as the most commonly diagnosed cancer during pregnancy (Psyrri & Burtness, 2005). Pregnancy-associated breast cancer (PABC) occurs in about 1 in 1,000 to 3 in 10,000 pregnancies (Hahn et al., 2006). As many women delay childbirth until age 30–40, the incidence of PABC is expected to rise (Psyrri & Burtness). In the United States, about 3,500 cases of breast cancer are diagnosed in pregnant women every year (Hassey Dow, 2000). A first pregnancy at 30 years of age or older and advanced maternal age are known risk factors for breast cancer (Psyrri & Burtness). The rate for women in their 40s having a first pregnancy has increased steadily since 1984. The number of women aged 30–34 years having a first pregnancy in 1975 has increased from 53 per 1,000 to 92 per 1,000 in 1997 and first-time mothers aged 35–39 years have risen from 36 per 1,000 in 1990 to 44 per 1,000 in 1997 (Keleher et al., 2002).

Breast cancer is classified as "pregnancy associated" if it is diagnosed during pregnancy or within one year of delivery (Hahn & Theriault, 2008). About 3% of all breast cancers are diagnosed during pregnancy (Ring, Smith, & Ellis, 2005). The average age at diagnosis for patients with PABC is 32–38 years (Keleher et al., 2002). A painless mass is palpated by the patient in 90% of reported cases (Scott-Conner, 1999). The incidence of breast cancer is the same in pregnant women as nonpregnant women in the general population. The hormonal and immunologic changes in pregnancy were presumed to provide a favorable environment for the growth of breast cancer cells, but multiple studies have failed to prove the theory (Scott-Conner).

The physiologic changes that take place in the breast during pregnancy can contribute to a delay in the diagnosis of PABC. In preparation for lactation, a women's breast size will nearly double in size and weight. The influence of estrogen and progesterone cause an increase in blood flow and fat, resulting in an increase in the size of milk-producing glands. Some women may begin to leak colostrum by 25 weeks gestation. Irritation of the breast ducts caused by rapid tissue growth may cause a bloody discharge, which usually is a benign condition (e.g., cells in the lining of the breast ducts being shed, secretion from a papilloma) (Imaginis, 2007). The areola also may increase in size and become darker in color. In addition, Montgomery tubercles, small nodules surrounding the areola, will produce a fluid to lubricate and cleanse the nipple in preparation for nursing (Imaginis).

A thorough baseline examination of the breast should be performed in the early stages of pregnancy before the physiologic changes are pronounced. Breast cancer most often presents as a painless lump or thickening, sometimes accompanied by a bloody discharge from the nipple (Eedarapalli & Jain, 2006). Palpating a mass is more difficult when the breast becomes engorged, and bloody discharge from the nipple often is dismissed as normal in pregnancy (Psyrri & Burtness, 2005); as a result, diagnosis and treatment often are delayed for two months or more (Hahn & Theriault, 2007). However, a delay of just one to two months can increase the chance of metastasis to the lymph nodes (Eedarapalli & Jain).

Diagnostic criteria for breast cancer are the same for pregnant and nonpregnant women. Triple assessment should be followed, starting with a thorough physical examination to assess for lumps and regional lymph nodes. The examination should be followed by a mammogram or ultrasound to determine whether the lump is a simple cyst or solid tumor. Ultrasound usually is the preferred diagnostic tool to differentiate benign cysts from solid tumors because the increased density of breast tissue in pregnancy makes mammograms less reliable (Hassey Dow, 2000). Breast magnetic resonance imaging has shown promise for improving accuracy in breast cancer diagnosis, but it has had limited use in pregnancy and is not recommended during the first trimester (Psyrri & Burtness, 2005). A fine needle biopsy should be done to determine the type of cancer; if the fine needle biopsy does not diagnosis the disease, a core needle biopsy can be performed (Dean, 2007). The assessment will help stage the cancer and determine a treatment course. After breast cancer has been diagnosed, additional examinations are needed to stage the disease. Chest x-ray with abdominal shielding, a liver function test, and an assessment of estrogen and progesterone receptor status should be done. Bones scans should be performed only if suspicion exists for bone metastasis (Hassey Dow).

A multidisciplinary approach is needed to care for pregnant women with breast cancer. Each patient and her family must be individually assessed to determine the need for support services, such as psychologists, social workers, and spiritual leaders, in addition to specialized maternal fetal medicine doctors and oncologists (Loibl et al., 2005). Psychological support is important to assist patients and families in making difficult treatment decisions and ensure that the treatment plan is followed. Some women may feel isolated, angry, and unable to express their fears; referral to peer support groups for women with cancer during pregnancy, such as Support for Cancer in Pregnancy (, may provide additional emotional support (Jack, 2006).

After a diagnosis of breast cancer has been made, treatment should not be delayed because of pregnancy. Surgery usually is the first step and can be done at any time without risk to the fetus (Hahn & Theriault, 2008). Modified radical mastectomy is the surgery of choice to avoid post-surgical radiation (Keleher et al., 2002). Breast-conserving surgery may be considered if the woman is diagnosed in the late second or early third trimester and radiation can be started immediately after delivery (Hahn & Theriault). Axillary dissection should be performed because metastasis is common in PABC. The presence of cancer in the lymph nodes will determine what type of chemotherapy will be used and whether radiation will be needed in the future (Eedarapalli & Jain, 2006). Women diagnosed in the late stages of the third trimester can elect for early delivery, which allows for breast-conserving surgery and immediate radiation treatment (Hassey Dow, 2000).

Chemotherapy generally is not given during the first trimester because of high risk for spontaneous abortion and fetal malformations (Ring et al., 2005). Chemotherapy is less likely to cause fetal malformations in the second and third trimesters when organ formation is complete; however, close monitoring of the fetus is necessary because about 50% of fetuses in PABC will have intrauterine growth restriction, preterm delivery, or lower birth weights (Hahn & Theriault). Mothers often request a delay in the start of chemotherapy because of concern for their child, but delays of three to six months have shown an increase in the risk of metastasis from 5%–10% (Keleher et al., 2002); therefore, nurses should review options with patients carefully and emphasize the importance of starting treatment promptly to improve outcomes. Chemotherapy should be stopped three to four weeks before the anticipated delivery to avoid myelosuppression, which can increase the risk for sepsis and hemorrhage for mothers and newborns (Ring et al.).

Radiation is used to treat localized areas of early breast cancer but is avoided in pregnancy; even with proper shielding of the abdomen, the fetus is exposed to therapeutic radiation and will be at risk for fetal malformations, hematologic disorders, and childhood malignancies (Hahn & Theriault).


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