Breast Cancer


Breast cancer is a disease in which cancer cells grow in the breast tissue.

Cancer occurs when cells in the body (in this case breast cells) divide without control or order. If cells keep dividing uncontrollably, a mass of tissue forms. This is called a growth or tumor.

The term cancer refers to malignant tumors. They can invade nearby tissue and spread to other parts of the body. Although most people think of breast cancer as affecting women, men can develop breast cancer as well. Breast cancer in men can be more aggressive.

Breast Cancer

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The cause of breast cancer is unknown. Research shows that certain risk factors are associated with the disease.

Risk Factors

Factors that increase your risk for breast cancer include:

  • Sex: female, although men can also get breast cancer
  • Age: 50 or older
  • 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)
  • Changes in certain genes (BRCA1, BRCA2, and others)
  • Race: Caucasian
  • 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
    • Taking hormone replacement therapy for long periods of time (Prempro for more than four years)
    • Tobacco use
  • Increased breast density (more lobular and ductal tissue and less fatty tissue)
  • Radiation therapy before the age of 30 years old
  • Overuse of alcohol

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. But as the cancer grows, it can cause the following changes:

  • A lump or thickening in or near the breast or in the underarm area or in the neck
  • A change in the size or shape of the breast
  • Nipple discharge or tenderness, or the nipple pulled back (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 symptoms should see a doctor.


The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include:

  • Clinical breast exam—the size and texture of the lump is manually examined to determines whether the lump moves easily
  • Mammography—x-rays of the breast used to see lumps or other changes in breast tissue
  • Ultrasonography—the use of high-frequency sound waves to see whether a lump is a fluid-filled cyst or a solid mass
  • Biopsy—removal of tumor tissue to be tested for cancer cells, types of biopsies for breast cancer include:
    • 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 suspicious 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
  • Tissue evaluation—breast cancer tissue is tested for the presence of estrogen and progesterone receptors, as well as the presence of HER2/neu which are used to help plan therapy.
  • Genetic testing—blood is evaluated for the presence of specific gene mutations in certain patients


Once breast cancer is found, staging tests are performed. This will help to find out if the cancer has spread and, if so, to what extent.

Treatments include:


  • Lumpectomy—removal of the breast cancer and some normal tissue around it. Often, some of the lymph nodes under the arm are removed.
    • May also be called tylectomy, segmentectomy, 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, without the intentional removal of the lymph nodes.
  • 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 if the cancer has spread to the chest muscles, and is rarely performed in the US at this time.
  • Modified radical mastectomy—removal of the whole breast, the lymph nodes under the arm and, often, the lining over the chest muscles.
  • Axillary lymph node dissection—removal of the lymph nodes under the arm to help determine whether cancer cells have entered the lymphatic system.
  • Sentinel lymph node biopsy—the placement, by the surgeon, of a small amount of blue dye and/or a radioactive tracer in the area where the tumor was located. The dye or tracer is then followed into the armpit and only those lymph nodes picking up the substance are removed. The accuracy rate for this procedure exceeds 95% in experienced hands and reliably identifies those lymph nodes that may contain cancer. Presently, 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. The potential side effects are far less than seen after a standard lymph node dissection.

Radiation Therapy

This is the use of radiation to kill cancer cells and shrink tumors. Two main types of radiation may be used:

External radiation therapy—radiation directed at the breast from a source outside the body

Internal radiation therapy—radioactive materials placed into the breast in or near the cancer cells


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

Biologic Therapy

The use of medications or substances made by the body to increase or restore the body's natural defenses against cancer. It is also called biologic response modifier (BRM) therapy.


Finding breast cancer early and treating it is the best way to prevent death from the disease. Because it does not cause symptoms in the early stages, it is important to have screening examinations and tests to find the cancer before symptoms appear.

  • Women age 20 or older should perform a breast self-exam (BSE) every month
  • Women between the ages of 20-39 should have a clinical breast exam by a health professional every three years
    • A breast exam should be performed more regularly if there is a family history or there have been previous breast biopsies
  • Women age 40 and older should have a screening mammogram every year
    • Some advocate that a mammogram should be performed sooner for patients with a strong family history or whom have had previous breast biopsies performed
  • After age 40, women should have a breast exam by a healthcare professional every year

Research showing that these steps actually lower the risk of dying from breast cancer is far from conclusive. The only exception is regular mammograms beginning at age 50. This clearly does decrease breast cancer mortality. A recent study involving 160,921 women recruited at age 39-41 showed that annual screening mammograms up to age 48 did decrease breast cancer mortality over an average of 10.7 years. This reduction, however, was not statistically significant. The results may be due to chance. According to these findings, about 2,500 women would need to be screened to prevent one breast cancer death during this time period. *


American Cancer Society



Canadian Breast Cancer Foundation

Canadian Cancer Society


Cancer of the female breast. National Cancer Institute website. Available at: Accessed July 11, 2008.

Learn about brest cancer. American Cancer Society website. Available at: Accessed July 11, 2008.

* Updated Prevention section on 12/21/2006 according to the following study, as cited by DynaMed's Systematic Literature Surveillance: Moss SM, Cuckle H, Evans A, Johns L, Waller M, Bobrow L; Trial Management Group. Effect of mammographic screening from age 40 years on breast cancer mortality at 10 years' follow-up: a randomised controlled trial. Lancet. 2006 Dec 9;368(9552):2053-60.

Last reviewed February 2008 by Rimas Lukas, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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