Key Points for This Section

Lactation (breast milk production) and breast-feeding should be stopped if surgery or chemotherapy is planned. Breast cancer does not appear to harm the fetus. Pregnancy does not seem to affect the survival of women who have had breast cancer in the past. Effects of certain cancer treatments on later pregnancies are not known.

Lactation (breast milk production) and breast-feeding should be stopped if surgery or chemotherapy is planned.

If surgery is planned, breast-feeding should be stopped to reduce blood flow in the breasts and make them smaller. Breast-feeding should also be stopped if chemotherapy is planned. Many anticancer drugs, especially cyclophosphamide and methotrexate, may occur in high levels in breast milk and may harm the nursing baby. Women receiving chemotherapy should not breast-feed. Stopping lactation does not improve survival of the mother.

Breast cancer does not appear to harm the fetus.

Breast cancer cells do not seem to pass from the mother to the fetus.

Pregnancy does not seem to affect the survival of women who have had breast cancer in the past.

Some doctors recommend that a woman wait 2 years after treatment for breast cancer before trying to have a baby, so that any early return of the cancer would be detected. This may affect a woman’s decision to become pregnant. The fetus does not seem to be affected if the mother has previously had breast cancer.

Effects of certain cancer treatments on later pregnancies are not known.

The effects of treatment with high-dose chemotherapy and a bone marrow transplant, with or without radiation therapy, on later pregnancies are not known.

Glossary Terms

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A procedure to replace bone marrow that has been destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own marrow saved before treatment), allogeneic (marrow donated by someone else), or syngeneic (marrow donated by an identical twin).

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

Treatment with drugs that kill cancer cells.

An anticancer drug that belongs to the family of drugs called alkylating agents.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

The developing offspring from 7 to 8 weeks after conception until birth.

An intensive drug treatment to kill cancer cells, but that also destroys the bone marrow and can cause other severe side effects. High-dose chemotherapy is usually followed by bone marrow or stem cell transplantation to rebuild the bone marrow.

A drug used to treat some types of cancer, severe skin conditions such as psoriasis, and rheumatoid arthritis. Methotrexate stops cells from making DNA. It is a type of antimetabolite. Also called amethopterin and Rheumatrex.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.