Ellen S. Weber, MSN
Below:
•Definition
•Purpose
•Description
•Preparation
•Aftercare
•Risks
•Key Terms
•Resources
Definition
Mammography is the study of the breast using x ray. The actual test is called a mammogram. There are two types of mammograms. A screening mammogram is ordered for women who have no problems with their breasts. It consists of two x-ray views of each breast. A diagnostic mammogram is for evaluation of new abnormalities or of patients with a past abnormality requiring follow-up (i.e. a woman with breast cancer treated with lumpectomy). Additional x rays from other angles or special views of certain areas are taken.
Purpose
The purpose of screening mammography is breast cancer detection. A screening test, by definition, is used for patients without any signs or symptoms in order to detect disease as early as possible. Many studies have shown that having regular mammograms increases a woman's chances of finding breast cancer in an early stage, when it is more likely to be curable. It has been estimated that a mammogram may find a cancer as much as two years before it can be felt. The American Cancer Society, American College of Radiology, American College of Surgeons and American Medical Association recommend annual mammograms for every woman beginning at age 40.
Screening mammograms usually are not recommended for women under age 40 who have no special risk factors and a normal physical breast examination. Below age 40, breasts tend to be "radiographically dense," which means it is difficult to see many details. In 2003, a new technique that introduces radiographic contrast into digital mammograms was proving useful at improving visibility of breast cancer in younger women. Screening mammograms can detect cancers in their earliest stages and greatly reduce mortality, particularly among women age 40 to 69. In fact, a study in 2003 found that women age 40 and older who had annual screening mammograms had better breast cancer prognoses because their cancers were diagnosed at earlier stages than women who had mammograms less often.
Some women are at increased risk for developing breast cancer, such as those with two or more relatives who have the disease. The 2003 American Cancer Society guidelines stated that women at increased risk might benefit from earlier screening mammograms and more frequent intervals for screening. However, the society suggested that evidence was not strong enough at that time to support making specific recommendations concerning screening examinations.
Diagnostic mammography is used to evaluate an existing problem, such as a lump, discharge from the nipple, or unusual tenderness in one area. The cause of the problem may be definitively diagnosed from this study, but further investigation using other methods may be necessary. This exam also is used to evaluate findings from screening mammography.
Description
A mammogram may be offered in a variety of settings. Hospitals, outpatient clinics, physicians' offices, or other facilities may have mammography equipment. In the United States, since October 1, 1994, only places certified by the Food and Drug Administration (FDA) are legally permitted to perform, interpret, or develop mammograms under the Mammography Quality Standards Act (MQSA).
In addition to the usual paperwork, a woman will be asked to fill out a form seeking information relevant to her risk of breast cancer and special mammography needs. The woman is asked about personal and family history of cancer, details about menstruation, child bearing, birth control, breast implants, other breast surgery, age, and hormone replacement therapy. Information about Breast Self Examination (BSE) and other breast health issues usually are available at no charge.
At some centers, a technologist may perform a physical examination of the breasts before the mammogram. Whether or not this is done, it is essential for the patient to tell the technologist about any lumps, nipple discharge, breast pain, or other concerns.
Clothing from the waist up is removed and a hospital gown or similar covering is put on. The woman stands facing the mammography machine. The technologist exposes one breast and places it on a plastic or metal film holder about the size of a placemat. The breast is compressed as flat as possible between the film holder and a rectangle of plastic (called a paddle), which presses down onto the breast from above. The compression should only last a few seconds, just enough to take the x ray. Good compression can be uncomfortable, but it is necessary to ensure the clearest view of all breast tissues.
Next, the woman is positioned with her side toward the mammography unit. The film holder is tilted so the outside of the breast rests against it, and a corner touches the armpit. The paddle again holds the breast firmly as the x ray is taken. This procedure is repeated for the other breast. A total of four x rays, two of each breast, are taken for a screening mammogram. Additional x rays, using special paddles, different breast positions, or other techniques are usually taken for a diagnostic mammogram.
The mammogram may be seen and interpreted by a radiologist right away, or it may not be reviewed until later. If there are any questionable areas or an abnormality, extra x rays may be recommended. These may be taken during the same appointment. More commonly, especially for screening mammograms, the woman is called back on another day for these additional films.
A screening mammogram usually takes approximately 15 to 30 minutes. A woman having a diagnostic mammogram can expect to spend up to an hour at the mammography facility.
The cost of mammography varies widely. Many mammography facilities accept "self referral." This means women can schedule themselves without a physician's referral. However, some insurance policies require a doctor's prescription to ensure payment. Medicare will pay for annual screening mammograms for all women with Medicare who are age 40 or older and a baseline mammogram for those age 35 to 39.
A digital mammogram is performed in the same way as a traditional exam, but the image is viewed on a computer monitor, stored as a digital file, and can be printed on film. Medicare now pays a small additional fee for digital mammography.
Preparation
The compression or squeezing of the breast for a mammogram is a concern for some women, but necessary to render a quality image. Even with concerns about pain, a 2003 study said that three-fourths of women reported the pain associated with a mammogram as four on a 10-point scale. Mammograms should be scheduled when a woman's breasts are least likely to be tender. One week after the menstrual period is usually best. The MQSA regulates equipment compression for consistency and performance.
Women should not put deodorant, powder, or lotion on their upper body on the day the mammogram is performed. Particles from these products can get on the breast or film holder and may look like abnormalities on the mammogram film.
Aftercare
No special aftercare is required.
Risks
The risk of radiation exposure from a mammogram is considered virtually nonexistent. Experts are unanimous that any negligible risk is far outweighed by the potential benefits of mammography.
Some breast cancers do not show up on mammograms, or "hide" in dense breast tissue. A normal (or negative) study is not a guarantee that a woman is cancer-free. Mammograms find about 85% to 90% of breast cancers.
"False positive" readings also are possible, and 5% to 10% of mammogram results indicate the need for additional testing, most of which confirm that no cancer is present.
Normal results
A mammography report describes details about the x ray appearance of the breasts. It also rates the mammogram according to standardized categories, as part of the Breast Imaging Reporting and Data System (BIRADS) created by the American College of Radiology (ACR). A normal mammogram may be rated as BIRADS 1 or negative, which means no abnormalities were seen. A normal mammogram may also be rated as BIRADS 2 or benign findings. This means that one or more abnormalities were found but are clearly benign (not cancerous), or variations of normal. Some kinds of calcification, lymph nodes, or implants in the breast might generate a BIRADS 2 rating. A BIRADS 0 rating indicates that the mammogram is incomplete and requires further assessment.
Abnormal results
Many mammograms are considered borderline or indeterminate in their findings. BIRADS 3 means an abnormality is present and probably (but not definitely) benign. A follow-up mammogram within a short interval of six months is suggested. This helps to ensure that the abnormality is not changing, or is "stable." This stability in the abnormality indicates that a cancer is probably not present. If the abnormality is cancerous, it will likely grow and change in the time between mammograms. Some women are uncomfortable or anxious about waiting and may want to consult with their doctor about having a biopsy. BIRADS 4 means suspicious for cancer. A biopsy is usually recommended in this case. BIRADS 5 means an abnormality is highly suggestive of cancer. The suspicious area should be biopsied.
Key Terms:
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Breast biopsy
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A procedure in which suspicious tissue is removed and examined by a pathologist for cancer or other disease. The breast tissue may be obtained by open surgery or through a needle.
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Radiographically dense
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Difficult to see details of breast tissue on x ray.
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Resources:
Resources
Books
- Henderson, Craig. Mammography & Beyond. Developing Technologies for the Early Detection of Breast Cancer: A Non-technical Summary. Washington, DC: National Academy Press, 2001.
- Love, Susan M., with Karen Lindsey. Dr. Susan Love's Breast Book, 3rd ed. Boulder, CO: Perseus Book Group, 2000.
Periodicals
- Letich, A., et al. "American Cancer Society Guidelines for the Early Detection of Breast Cancer: Update 1997." CA: A Cancer Journal for Clinicians 47 (May/June 1997): 150-53.
- "Mammography in Women Over Forty Catches Disease Earlier." Women's Health Weekly (August 14, 2003): 14.
- "New Digital Technique Improves Mammography Results." Women's Health Weekly (September 18, 2003): 28.
- Smith, Robert A., et al. "American Cancer Society Guidelines for Breast Cancer Screening: Update 2003." Cancer (May-June 2003): 141-170.
- "Stress -Not Pain- Is Major Barrier to Mammography." Contemporary OB/GYN (July 2003): 17.
- "The Mammography Muddle." Harvard Women's Health Watch 7 (March 1997): 4-5.
- Weber, Ellen. "Questions and Answers About Breast Cancer Diagnosis." American Journal of Nursing (October 1997): 34-8.
Organizations
- American Cancer Society. 1599 Clifton Rd., Atlanta, GA 30329. (800) ACS-2345. http://www.cancer.org.
- U.S. Food and Drug Administration. 5600 Fishers lane, Rockville, MD 20857. (800) 532-4440. http://www.fda.gov.;
- National Cancer Institute. Office of Cancer Communications, Bldg. 31, Room 10A31, Bethesda, MD 20892. NCI/Cancer Information Service: (800) 4-CANCER. http://cancernet.nci.nih.gov.
