Glossary

Here are some terms that you may encounter when you talk to your doctor about breast cancer treatment or during your search for information.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Adjuvant
In breast cancer, adjuvant treatment is given in addition to your primary or initial treatment (surgery with or without radiation) to help prevent or delay cancer cells from multiplying.
Adrenal glands
Glands located above the kidneys that make hormones, such as androgens, cortisol, and aldosterone.
Aldosterone
A hormone produced by the adrenal glands.
Androgens
Hormones made by the adrenal glands that are turned into estrogen by the enzyme aromatase.
Antiestrogen
Any agent or drug that blocks the effects of estrogen; these medications are used to treat breast cancers that depend on estrogen for growth.
Aromatase
The enzyme that changes androgens made by the adrenal glands into estrogen.
Aromatase inhibitors
Drugs called aromatase inhibitors are a type of hormonal treatment that reduces the action of aromatase, an enzyme needed to make the hormone estrogen.

B

Breast cancer
Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk).

C

Chemotherapy
See cytotoxic chemotherapy.
Clinical trial
A medical study that tests the safety and effectiveness of a drug or treatment in people.
Cytotoxic chemotherapy
Treatment with drugs that attack and kill cancer cells and rapidly growing normal cells.

E

Enzymes
Proteins that are produced in cells and that affect chemical reactions.
Estradiol
A common form of estrogen in women. At menopause, the ovaries stop producing estradiol, and levels are therefore very low in postmenopausal women.
Estrogen
A female hormone; one of the hormones that can help some breast cancer tumors grow.
Estrone
The most common form of estrogen in postmenopausal women. Estrone is stored in fatty tissues.

H

Hormonal treatment
In breast cancer treatment, hormonal treatment is the use of drugs to block the effects or production of estrogen.
Hormone receptor
A protein on the surface of a cell that recognizes and binds with specific hormone molecules.
Hormone receptor-negative (estrogen receptor-negative)
In breast cancer, this means the tumor cells do not have hormone receptors (see hormone receptor, above) and therefore do not depend on hormones to grow.
Hormone receptor-positive
In breast cancer, this means the tumor cells have hormone receptors (see hormone receptor, above) and therefore depend on hormones to grow.
Hormone replacement therapy (HRT)
Drug therapy that supplies estrogen (with or without progestin) to women in order to help reduce menopausal symptoms.
Hormones
Substances produced by organs or cells in the body that affect bodily processes.

I

Invasive cancer
Cancer that spreads outside the tissue where it initially developed and grows into nearby, healthy tissues.

L

LHRH (luteinizing hormone–releasing hormone)
A class of hormonal agents that affect the production of certain hormones.
Lobule
A small lobe, which is a section of the breast, or subdivision of a lobe. In the breast, lobules produce milk.
Locally advanced
In breast cancer, tumors measuring 5 cm (2 inches) or more in diameter and that may or may not have spread to nearby lymph nodes or other tissues.
Lumpectomy
Surgical removal of the breast tumor and a small amount of surrounding tissue.
Luteinizing hormone (LH)
A hormone secreted by the pituitary gland. LH stimulates the secretion of sex hormones in both men and women.
Lymph
A clear fluid that travels through lymph vessels carrying immune-system cells and tissue waste products.
Lymph nodes
Small, bean-shaped collections of tissue found near the breast under the arm, above the collarbone, in the chest, and in many other parts of the body. Lymph nodes filter lymph, and store immune cells such as lymphocytes.
Lymphatic system
Tissues and organs that produce and carry white blood cells that fight infection. The system includes a network of thin tubes that carry lymph and white blood cells. The tubes branch into all tissues of the body.
Lymphedema
A condition in which fluid does not drain from the lymph nodes, causing swelling. Sometimes this happens in the arm after lymph nodes have been removed from the underarm. It can also happen after radiation therapy.
Lymphocyte
A type of white blood cell. Lymphocytes are responsible for certain types of immunity; they also produce antibodies and other substances that fight infection and disease.

M

Malignant
Cancerous. Malignant tumors and cells are able to grow into surrounding tissue and spread to other parts of the body.
Margin
The tissue around the edge of the mass (tumor) removed in cancer surgery. If the pathologist sees no cancer cells in the margin, it is called negative or "clean." If the pathologist finds cancer cells in the margin, it is called positive, and it means that there might be cancer cells left in the area of the surgery that were not removed.
Mastectomy
Surgical removal of the entire breast, most of the lymph nodes under the arm, and sometimes the lining over the chest muscles.
Menopause
The time in a woman's life when the ovaries stop producing eggs and she permanently stops having menstrual periods.
Metastasis
The spread of cancer from one part of the body to another.
Metastatic
In breast cancer, cancer that has spread from the breast to other parts of the body, such as the bone, lungs, liver, or brain.

O

Osteoporosis
A condition that is marked by a decrease in bone mass and density, causing bones to become fragile.

P

Postmenopausal
The stage in a woman's life following her final menstrual period.
Progesterone
A female hormone; one of the hormones that can help some breast cancer tumors grow.

R

Radiation
See radiation therapy.
Radiation therapy
In cancer treatment, use of x-rays, gamma rays, and alpha and beta particles to destroy cancer cells.
Receptor
A specific molecule of a cell that recognizes and binds with other specific molecules, such as hormones.
Recurrence
A return of cancer after primary (initial) treatment, either at the same site as the original, primary tumor or somewhere else in the body.

S

Stage
The term used to describe the system of classification that identifies the extent of cancer within the body.
Steroid hormones
Chemicals made by ovaries and adrenal glands that have a common structure, such as estrogen, testosterone, and cortisone.