Breast cancer is a malignant tumor that starts from the cells of the breast.

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

Risk Factors

This cancer can occur in both men and women, although male breast cancer is rare. Breast cancer is the most frequently diagnosed cancer in women, and any woman can develop it. However, several risk factors may increase the likelihood. Risk factors that can't be changed include:

  • Race/ethnicity: Caucasian women develop breast cancer slightly more often than African-American women. However, African-American women tend to die of breast cancer more often. This may be partly because they often develop a more aggressive type of tumor.

  • Aging: Two out of three women with invasive cancer are diagnosed after age 55.

  • Personal history of breast cancer

  • Previous breast irradiation

  • Family history and genetic factors: Having a close relative, such as a mother or sister, with breast cancer increases the risk.

  • Benign breast disease

  • Dense breast tissue

  • Diethylstilbestrol (DES) exposure

  • Previous breast biopsy in which the tissue showed atypical hyperplasia

  • Menstrual periods that began before age 12

  • Menopause that began after age 55

Breast Cancer Symptoms

  • A lump or thickening in the breast or under the arm
  • A clear or bloody discharge from the nipple
  • Crusting or scaling of the nipple
  • A nipple that that becomes inverted (no longer sticks out)
  • Redness or swelling of the breast
  • Dimpling on the breast skin resembling the texture of an orange
  • A change in the contours of the breast, such as one being higher than the other
  • A sore or ulcer on the skin of the breast that does not heal

The most frequently cited lifestyle-related risk factors include:

  • Not having children or having your first child after age 30

  • Oral contraceptive use

  • Physical inactivity

  • Alcohol use

  • Long-term, postmenopausal use of combined estrogen and progestin (HRT)

  • Weight gain and obesity after menopause


How is breast cancer diagnosed? First of all, it's important to remember that a lump or other changes in the breast, or an abnormal area on a mammogram, may not be a sign of cancer.

To determine the cause of any symptoms, your doctor will perform a careful physical exam that includes taking your personal and family medical history. The exam may include palpation, or feeling the lump and the tissue around it--its size, its texture, and whether it moves easily. Fluid may be collected from spontaneous nipple discharge and sent to a lab to look for cancer cells. Most nipple secretions are not cancer; they may be caused by an injury, infection, or benign tumor.

For women at high risk for breast cancer, a diagnostic procedure called ductal lavage may be used. Cells are collected from inside the milk ductal system, the location where most breast cancers begin.

In addition to a physical exam, an imaging test will be performed, including one or more of the following:

  • Diagnostic mammography: An X-ray used to diagnose unusual breast changes.

  • Digital mammography: Images are electronically captured and stored on a computer rather than X-ray film. The images can be manipulated to help visualization.

  • Ultrasonography: Uses high-frequency sound waves that produce a picture called a sonogram.

  • Scintimammography: A specialized radiology procedure used when other exams are inconclusive.

  • Magnetic resonance imaging (MRI): Uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images.

Based on the results, your doctor may decide that no further tests are needed and no treatment is necessary. In such cases, he or she may want to check you regularly to watch for any changes.

Often, however, the doctor must remove fluid or tissue from the breast to be sent to a lab to look for cancer cells. This procedure, called a biopsy, may be performed using a needle to acquire a tissue sample or by a surgical method. There are several types of breast biopsy procedures; the type performed depends on the location and size of the breast abnormality.


Treatment for breast cancer can include surgery, radiation, chemotherapy, or hormone therapy. The good news is that breast cancer death rates have been going down. This is likely the result of earlier detection and better treatment.

Medical Reviewer: [Foster, Sara M. RN, MPH, Stump-Sutliff, Kim RN, MSN, AOCNS] Last Annual Review Date: 2009-07-03T00:00:00-06:00 Copyright: © 2000-2010 The StayWell Company, 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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On the day of your mammogram, it's important that you don't wear deodorant.