Breast Cancer and Pregnancy
About 1 in 3,000 pregnancies involves a mother with breast cancer. In fact, breast cancer is the most common cancer in women who are pregnant or who have just had a baby. The average woman with breast cancer is between 32 and 38 years old. Since many women are having children later in life, the numbers of pregnant women with breast cancer will probably increase.
Women who are pregnant or nursing usually have tender, swollen breasts. That makes small lumps hard to detect, possibly leading to a delay in finding breast cancer. In pregnant women, these delays are common. The average reported delay is 5 to 15 months between the start of symptoms and the diagnosis. Because of this delay, cancers are usually detected at a later stage in pregnant women than in women who are not pregnant.
To detect breast cancer, pregnant and nursing women should examine their breasts. In addition, they should have a breast examination by a doctor as part of the routine prenatal care. If an abnormality is found, ultrasound and a mammogram can be performed with little risk to the fetus. An ultrasound is a test that uses sound waves to find tumors. A mammogram is a special x-ray of the breast. It can find tumors that are too small to feel. Twenty-five percent of mammograms in women who are pregnant may be negative even when cancer is present. Therefore, a biopsy is important for the diagnosis of any mass that can be felt. A biopsy involves the removal of cells or tissues that are then examined under a microscope.
Stage Explanation
Once cancer is diagnosed, more tests are needed. These tests are to find out if the cancer has spread from the breast to other parts of the body. The process of finding this out is called staging. A doctor needs to know the stage of the disease to plan treatment. For women who are pregnant and have breast cancer, the normal procedures used for staging can be changed slightly to make them safer. Blood tests may also be used.
For pregnant women with breast cancer, overall survival may be worse at all stages than for non pregnant women. This may have nothing to do with the pregnancy. It actually may be due to the delayed diagnosis. Ending the pregnancy does not seem to affect the outcome of breast cancer. Consequently, it is not usually considered as a treatment option. It may be considered, however, if the treatment options for the mother are severely limited by the pregnancy. This, of course, depends on the age of the developing fetus.
Treatment for Early Stage Cancer (Stages I & II)
Radiation therapy may be harmful to the fetus. Consequently, it should not be used during pregnancy. Surgery is the recommended first treatment in pregnant women with breast cancer. Modified radical mastectomy is the preferred choice. However, conservative surgery with radiation therapy after the baby is born has been used to keep the breast intact. Chemotherapy may be needed after surgery. It should not, though, be given during the first 3 months of the pregnancy. After this time, chemotherapy does not usually lead to birth defects. It may, though, cause early labor and low birth weight. It’s unknown what the risk of using hormones — alone or with chemotherapy — after surgery is.
Treatment for Late Stage Disease (Stages III & IV)
Radiation therapy should be avoided during the first three months of pregnancy. So should chemotherapy. Chemotherapy may be given, though, after the first three months as discussed above.
Abortion as a treatment option does not improve survival for the mother. However, only 10% of women with stage III or IV disease live 5 years. That means the mother may have a limited time to live. Since there is also a risk of damage to the fetus during treatment, continuing the pregnancy should be discussed with the mother and her family.
Breast-Feeding
Stopping milk production does not improve survival of the mother. However, if surgery is planned, breast-feeding should be stopped to make the breasts smaller and lessen the blood flow in them. It should also be stopped if chemotherapy is planned. Many drugs, especially cyclophosphamide and methotrexate, may occur in high levels in breast milk. Those levels would affect the nursing baby. In general, women receiving chemotherapy should not breast-feed.
Effects of Cancer on the Fetus
Breast cancer cells do not seem to be transferred to the fetus from the mother. So, breast cancer does not appear to damage the fetus.
Effect of Pregnancy in Patients Who Have Previously Had Breast Cancer
Pregnancy does not seem to affect the survival of women who have had breast cancer in the past. Nor does the fetus seem to be affected. Some doctors recommend that a woman should wait two years before trying to have a baby. That way, any early return of the cancer would be detected. An early return may affect a woman's decision to be a parent. It’s not known what the risks in pregnancy are after a woman has received a bone marrow transplant and high-dose chemotherapy. That uncertainty remains whether she had or did not have total body irradiation. The procedures, though, may result in early labor and low birth weight.
