Dr. Susan Love Research Foundation | Breast Cancer

For women who learn they have breast cancer while pregnant, a new study provides reassurance that chemotherapy appears safe during the second and third trimesters.

Breast cancer is rare during pregnancy. It is estimated that less than 4 percent of women are diagnosed with breast cancer during this time. But when it does occur, cancer treatments must be given in a way that will protect the fetus while not compromising the woman's own chance for survival.

For this study, a group of British researchers reviewed records from five hospitals in London to gather information about women who had received chemotherapy for breast cancer while pregnant. They identified 63 women who were pregnant at the time their breast cancer was diagnosed; 28 of these women had chemotherapy while pregnant. The women were between 28 and 42 years of age. All were between 5 and 29 weeks pregnant.

Seventeen women had surgery while pregnant. Four had surgery after delivery. Seven women had neoadjuvant chemotherapy (treatment given before surgery) to reduce tumor size or following a diagnosis of inflammatory breast cancer, and 17 women received adjuvant chemotherapy (treatment given after surgery). Four women received chemotherapy to treat metastatic disease.

All of the women were between 15 and 33 weeks pregnant; 22 started chemotherapy during the second trimester and five during the third trimester. One woman received chemotherapy in the first trimester. She was not aware she was pregnant at the time, and later had a miscarriage.

The records indicated that chemotherapy did not cause any abnormalities in the children that were born. Based on their findings, the researchers concluded "women should not be denied the potential benefits of chemotherapy because they are pregnant at the time of their breast cancer diagnosis."

Susan says:
During the first trimester of pregnancy the fetus is developing all of its organs. During this time, chemotherapy can be dangerous for the fetus, and has been found to result in a higher chance of either miscarriage or birth defects. After the first trimester, the fetus is fully developed, and chemotherapy carries far fewer risks. Neither this study nor two previous studies have identified any babies born with birth defects to women who received chemotherapy after their first trimester.

Researchers have reported that some women who were given chemotherapy while pregnant have developed preeclampsia, went into preterm labor, or had a baby with a low birth weight. There also has been one report of intrauterine death. It's not clear, though, whether these medical problems or the one death were due to the chemotherapy or would have occurred anyway. In this study, none of the babies had a birth weight below the 10th percentile. Two experienced respiratory distress, and five had to be transferred to a neonatal unit. Each of these babies ended up being fine.

There is very little data on what happens to children exposed to chemotherapy in utero as they grow older. To date, though, there are no indications that they have been negatively affected.

It is frightening to be diagnosed with breast cancer while pregnant. This study should reassure women that being treated with chemotherapy while pregnant will increase their own chance of survival and is unlikely to have any serious long-term effects on their baby.

Additional Information:
1999 French study, "Chemotherapy for Breast Cancer During Pregnancy."