Breast cancer is a disease in which cancer cells grow in the breast tissue. It is the most common cancer in women in the United States. The normal breast consists of glandular tissue called lobes. These lobes are sectioned off into lobules, which produce milk. Milk is carried to from the lobules to the nipple by small ducts. All this tissue is surrounded by fatty and connective tissue, as well as blood and lymph vessels.

Types of breast cancer found in women are:

  • Ductal carcinoma situ—Early stage cancer confined to the ducts. This type has a high cure rate.
  • Lobular carcinoma in situ (LCIS)—Most doctors consider the finding of LCIS to be incidental, and it is thought to be a marker for breast cancer risk. Women with LCIS seem to have a 7-10 times increased risk of developing some form of breast cancer (usually infiltrating lobular carcinoma) over the next 20 years.
  • Infiltrating ductal carcinoma—A cancer that starts in the ducts of the breast and spreads into surrounding tissues. This is the most common type of breast cancer in women.
  • Infiltrating lobular carcinoma—A cancer that starts in the lobules of the breast and spreads into surrounding tissues.
  • Medullary, mucinous, and tubular carcinomas—These are three relatively slower-growing types of breast cancer.
  • Inflammatory carcinoma—A rare and aggressive form of breast cancer that can be difficult to treat. This cancer invades the lymphatic vessels of the skin and can be very extensive. It is very likely to spread to the local lymph nodes.
  • Paget's disease—A very rare cancer of the areola and nipple. Although Paget's does not arise from glandular tissue in the breast, it can be associated with both in situ and infiltrating breast cancers.

Breast Cancer

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Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths can invade nearby tissues including the lymph nodes. Cancer that has invaded the lymph nodes can then spread to other parts of the body. The lymph nodes associated with breast cancer are in the armpit, above the collarbone, and in the chest.

It is not clear exactly what causes these problems in the cells, but is probably a combination of genetics and environment.

Risk Factors

Breast cancer is more common in Caucasian women, aged 50 years and older. Other factors that may increase your chance of breast cancer include:

  • Personal history of breast cancer
  • Family members with breast cancer
  • Changes in breast tissue, such as atypical ductal hyperplasia, radial scar formation, and lobular carcinoma in situ (LCIS)
  • Genetic mutations, such as BRCA1, BRCA2, and others
  • Excess body weight, particularly after menopause
  • Consuming a diet that is high in red meat
  • Increased exposure to estrogen over a lifetime through:
    • Early onset of menstruation
    • Late onset of menopause
    • No childbearing or late childbearing
    • Absence of breast-feeding
    • Hormone replacement therapy
  • Increased breast density—more lobular and ductal tissue and less fatty tissue
  • Radiation therapy before the age of 30 years old
  • Smoking
  • Excessive alcohol use

Note: Studies show that most women with known risk factors do not get breast cancer. Many women who get breast cancer have none of the risk factors listed above except age.


When breast cancer first develops, there may be no symptoms at all. As the cancer grows, it can cause the following changes:

  • One or more lumps in the breast which may or may not be painful
  • One or more lumps in lymph nodes near the breast, under your arm, or collarbone which may or may not be painful
  • Thickening in or around the breast
  • A change in the size or shape of the breast
  • Nipple discharge or tenderness, or the nipple inverted into the breast
  • Ridges or pitting of the breast skin, like the skin of an orange
  • A change in the way the skin of the breast, areola, or nipple looks or feels (for example, warm, swollen, red, or scaly)

Note: These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these should see a doctor.


The doctor will ask about your symptoms and medical history. A physical exam will be done. It will include a breast exam and blood tests.

Imaging tests can help diagnose and evaluate the extent of the cancer. Imaging tests include:

Your doctor may need to test your breast tissue and adjacent lymph nodes. A sample will be removed and sent to a lab to look for cancer cells. This can be done with different biopsy types, including:

  • Fine-needle aspiration—Removal of fluid and/or cells from a breast lump using a thin needle.
  • Needle biopsy —Removal of tissue with a needle from an area that looks unusual on a mammogram but cannot be felt.
  • Surgical biopsy:
    • Incisional biopsy—Cutting out a sample of a lump or suspicious area.
    • Excisional biopsy—Cutting out all of a lump or suspicious area and an area of healthy tissue around the edges.

If cancer is present, your doctor may order tests to learn about the type of cancer. These may include:

  • Blood tests—To look for tumor markers or genetic mutations.
  • Tissue evaluation—To look for estrogen and progesterone receptors, and the presence of HER2/neu and Oncotype DX. These are used to help plan therapy.

The physical exam combined with all of your test results, will help to determine the stage of cancer you have. Staging is used to guide your treatment plan. Like other cancers, breast cancer is staged from I-IV. Stage I is a very localized cancer, while stage IV indicates a spread to other parts of the body.


Cancer treatment varies depending on the stage and type of cancer. A combination of therapies is most effective. For example, radiation may be used before surgery to shrink the tumor or after to make sure all the cancer has been removed.

Treatment options include:


The goal of surgery is to remove the tumors and any affected tissue.

  • Lumpectomy —Removal of the breast cancer and some normal tissue around it. Often, some of the lymph nodes under the arm are also removed. This may also be called tylectomy or quadrantectomy.
  • Segmentectomy—Removal of the cancer and a larger area of normal breast tissue around it.
  • Simple mastectomy —Removal of the breast, or as much of the breast as possible. If the surgeon removes some lymph nodes for biopsy, it is done with a separate incision. This is the most common surgery for breast cancer treatment.
  • Skin-sparing mastectomy—The same amount of tissue is removed as with a simple mastectomy, but the skin over the breast is spared. This can be used when immediate breast reconstruction surgery is planned. A variation of this procedure also can spare the nipple and areola. This may not be an option for all women.
  • Modified radical mastectomy—Removal of the whole breast, the lymph nodes under the arm and, often, the lining over the chest muscles.
  • Radical mastectomy—Removal of the breast, both chest muscles, the lymph nodes under the arm, and some additional fat and skin. This procedure is only considered in rare cases. It is done if the cancer has spread to the chest muscles.
  • Sentinel lymph node biopsy —A small amount of blue dye and/or a radioactive tracer is placed in the area where the tumor was located. The lymph nodes that pick up the substance are removed. Those remaining lymph nodes should be removed if any sentinel nodes contain cancer. This method is usually done in women who do not have lymph nodes that can be felt in the armpit.
  • Axillary lymph node dissection—Removal of the lymph nodes under the arm. This is done to help determine whether cancer cells have entered the lymphatic system.
  • Cryotherapy—Extreme cold is used to freeze and destroy cancer cells. Cryotherapy is considered to be experimental at this time.
Radiation Therapy

Radiation therapy is the use of radiation to kill cancer cells and shrink tumors. The main types of radiation include:

  • External radiation therapy—Radiation directed at the breast from a source outside the body.
  • Internal radiation therapy—Radioactive materials are placed into the breast in or near the cancer cells.
  • Microwave thermotherapy—Used to bring cancer cells to a high temperature. This may make them more sensitive to when exposed to traditional radiation therapy treatment. It is early in the research process and may not be available in all areas.

Chemotherapy is the use of drugs to kill cancer cells. It may be given in many forms including pill, injection, or IV. The drugs enter the bloodstream. They travel through the body killing mostly cancer cells. Some healthy cells are killed as well.


The following therapies may be used in conjunction with chemotherapy:

  • Biologic therapy —The use of medications or substances made by the body to treat cancer. Biologic response modifier (BRM) therapy is the use of medications to increase or restore the body's natural defenses against cancer.
  • Targeted therapy —Treats specific characteristics of cancer cells by altering how the body responds to them. For example, medications can block the growth of new blood vessels or block chemical signals that allow cancer cells to grow and function.
  • Hormone blocking therapy —Designed to take advantage of the fact that many breast cancers are estrogen sensitive. Estrogen binds to the estrogen-sensitive cells and stimulates them to grow and divide. Anti-estrogen drugs prevent the binding of estrogen. This stops the cells from growing and prevents or delays breast cancer from returning.
Other Medications

Cancer treatments can cause some side effects like nausea, anemia, pain, or bone loss. Other medications or treatments may be needed to minimize these problems throughout your cancer treatment.


Finding breast cancer early and treating it is the best way to prevent death from the disease. Breast cancer does not cause symptoms in the early stages. It is important to have screening exams and tests. These steps can help to find the cancer before symptoms appear. The following recommendations are for women with no symptoms who are not high risk for breast cancer:

  • Mammograms:
    • Age 40-49—recommendations vary from waiting until age 50 to having the screening every 1-2 years
    • Age 50-74—ranges from every 1-2 years
  • Clinical breast exam:
    • Age 20-39—ranges from 1-3 years
    • Age 40 and older—every year
  • Breast self-exam is optional for those age 20 and older. Talk to your doctor about the risks and benefits.

If you have an increased risk of breast cancer, you may need to start having mammograms earlier. You and your doctor can decide on the best screening schedule for you. It is important to note that mammograms are the most sensitive test currently used to evaluate the breast, but they will miss 10-15% of breast cancers. Mammograms also have a false positive result about 33% of the time. A false positive result occurs when a test suggests an illness that actually does not exist.

There are 2 medications to prevent breast cancer in high-risk, postmenopausal women. These medications increase your chances of having blood clots and stroke. Talk to your doctor about whether medication is right for you.

If you are at very high risk for breast cancer, surgery to remove your breasts before you get cancer (a procedure called prophylactic mastectomy) may be an option.