Pregnancy and breast cancer

Last Modified: January 10, 2006

Dear OncoLink "Ask The Experts,"

How is breast cancer managed in a patient who just found out she is pregnant?

Carolyn Vachani RN, MSN, AOCN, OncoLink's Nurse Educator, responds:

Approximately 1 to 3 patients out of 10,000 deliveries will be diagnosed with breast cancer during their pregnancy. It is the most common cancer seen during pregnancy. Recent tendencies to defer childbearing until later in life may increase the incidence, since older women are more likely to develop breast cancer.

The clinical presentation of breast cancer during pregnancy is the same as in a nonpregnant patient, with a palpable mass being the most common symptom. Mammography is not particularly helpful in the pregnant women because of the increased density of the breast tissue during pregnancy, but ultrasound can safely be used. Biopsy of the lump can be performed safely by a physician experienced in such cases.

The options for the local treatment of breast cancer during pregnancy are limited for the woman who wishes to continue her pregnancy. The use of radiation therapy during the first and second trimester of pregnancy is contraindicated due to the inability to shield the fetus from radiation. For the third trimester of pregnancy, lumpectomy with or without axillary lymph node dissection can be performed, with radiation therapy delayed until after delivery. In general, most would advise modified radical mastectomy to avoid the problems of radiation therapy during pregnancy, including the risk to the fetus. Alternatively, therapy can be postponed which increases risk to the mother. In some instances, when cancer is diagnosed near term, delivery may be accomplished prior to surgery for the breast cancer. In rare cases, a locally aggressive malignancy diagnosed very early in pregnancy and requiring radiation therapy may justify a therapeutic abortion.

All chemotherapeutic agents are potentially teratogenic (dangerous to the fetus) during the first trimester. However, studies have safely given chemotherapy to pregnant women in the 2 nd & 3 rd trimesters. Before administering chemotherapy to such patients, they must be willing to accept the risks of premature delivery as a consequence of treatment.

Breast cancer during pregnancy had been thought to be a particularly virulent disease, but much of the poor prognosis seems to have been due to advanced disease at the time of diagnosis. Stage-for-stage, current studies show equivalent survival when women who develop breast cancer during pregnancy are compared with the general population of breast cancer patients.