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Breast Cancer 101

What is Breast Cancer?

Cancer is the name of a large group of diseases in which abnormal cells grow in an uncontrolled way. In most cancers, this rapid cell growth eventually forms a potentially dangerous lump of cells, or tumor. Over time, cancer cells can invade other parts of the body and interrupt normal body function, and can ultimately lead to death. All cancers are named for the place in the body where the abnormal cell growth started.

Breast cancer is a group of cancerous, or malignant, cells that originates in the tissue of the breast. Although men can get the disease, nearly all cases of breast cancer occur in women. After skin cancer, it is the most common form of cancer among women. Most breast cancers begin in the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk).

Breast Cancer Glossary

Adjuvant therapy

Treatment provided in addition to surgery. Administered when all detectable cancer has been removed, but the risk of relapse remains. Examples include radiation, chemotherapy, and hormonal therapy.

Areola

The pigmented area of skin that surrounds the nipple.

Aromatase inhibitor

A class of drugs that either decreases the production of estrogen or blocks the action of estrogen on receptors.

Axilla

The underarm

Benign tumor

A non-cancerous lump of cells that does not spread to nearby tissues or other parts of the body.

Breast Self-Exam (BSE)

The breast self-exam is a visual and tactile inspection of a woman’s breasts, performed by the woman herself. The purpose of a BSE is for a woman to become familiar with the normal look and feel of her own breasts, so that she can then detect abnormal lumps that may be cancerous. The BSE is not a substitution for screening tests such as mammography, but according to the American Cancer Society, 25 percent of all breast cancers are detected by BSE’s! Check Your Self!

Carcinoma

A cancer that begins in the cells that line an organ such as the breast. Most breast cancers are carcinomas.

Chemotherapy

Treatment with anticancer drugs. Chemotherapy may be given to patients with breast cancer to kill any microscopic cancer cells within the breast tissue or in the rest of the body.

Cyst

A closed sac filled with fluid.

Duct

A tube in the breast through which milk passes from the lobules to the nipple

Ductal carcinoma in situ

Cancer that remains localized in the ducts of the breast and has not spread into surrounding tissue.

Estrogen

A steroidal hormone. In women, estrogen is primarily produced by the ovaries and is responsible for regulating the development of secondary sex characteristics, regulating menstruation, and preparing the uterus for reproduction.

Lobular carcinoma in situ

Proliferation of cells in the lobules of the breast. This can indicate a risk of future cancer, but is not considered a cancer.

Lumpectomy

Surgery to remove only the cancerous breast lump. It is usually followed by radiation therapy, serving to preserve the natural appearance of the breast.

Lymphedema

An abnormal buildup of fluid that causes swelling, most often in the arms or legs. Lymphedema develops when lymph vessels are missing, impaired, damaged, or removed.

Malignant

Cancerous. Malignant cells grow, invade, and can spread to other parts of the body.

Mammogram

A series of X-rays of the breast used to detect abnormal growths or changes in the breast tissue.

Mastectomy

Surgery to remove the breast.

Progesterone

Female sex hormone involved in the female menstrual cycle, pregnancy and embryogenesis.

Radiation therapy

A form of cancer treatment that uses high levels of radiation to kill cancer cells or keep them from growing and dividing, while minimizing damage to healthy cells.

Relapse

A reoccurrence of cancer after a partial recovery.

Stages of Breast Cancer

Stage 0

Stage 0 describes non-invasive breast cancers. There is no evidence of cancer cells invading neighboring tissue.

Stage 1

Stage I describes invasive breast cancer in which the tumor measures up to 2 centimeters. No lymph nodes are involved at this stage.

Stage II

Stage II is divided into subcategories known as IIA and IIB.

Stage IIA

Stage IIA describes invasive breast cancer in which:

No tumor can be found in the breast, but cancer cells are found in the lymph nodes.
The tumor measures 2 centimeters or less and has spread to the lymph nodes.
The tumor is from 2 centimeters to 5 centimeters and has not spread to the lymph nodes.

Stage IIB

Stage IIB describes invasive breast cancer in which:

The tumor is from 2 centimeters to 5 centimeters and has spread to the lymph nodes.
The tumor is larger than 5 centimeters but has not spread to the lymph nodes.

Stage III

Stage III: Stage III is divided into subcategories known as IIIA, IIIB, and IIIC.

Stage IIIA

Stage IIIA describes invasive breast cancer in which:

No tumor is found in the breast. Cancer is found in lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone.
The tumor is 5 centimeters or smaller and has spread to lymph nodes that are clumped together or sticking to other structures
The tumor is larger than 5 centimeters and has spread to lymph nodes that are clumped together or sticking to other structures.

Stage IIIb

Stage IIIB describes invasive breast cancer in which:

The tumor may be any size and has spread to the chest wall and/or skin of the breast.
The tumor may have spread to lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone.

Stage IIIC

Stage IIIC describes invasive breast cancer in which:

There may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast.
The cancer has spread to lymph nodes above or below the collar bone.
The cancer may have spread to lymph nodes or to lymph nodes near the breastbone.

Stage IV

Stage IV: Stage IV describes invasive breast cancer in which the cancer has spread to other organs of the body — usually the lungs, liver, bone, or brain.