What is a mammogram?
A mammogram is an x-ray examination of the breast. It is used to detect and diagnose breast disease in women who either have breast problems such as a lump, pain, or nipple discharge, as well as for women who have no breast complaints.
Mammography cannot prove that an abnormal area is cancer, but if it raises a significant suspicion of cancer, tissue will be removed for a biopsy. Tissue may be removed by needle or open surgical biopsy and examined under a microscope to determine if it is cancer.
Mammography has been used for about 40 years, and in the past 15 years technical advancements have greatly improved both the technique and results. Today, dedicated equipment, used only for breast x-rays, produces studies that are high in quality but low in radiation dose. Radiation risks are considered to be negligible.
What are the different types of mammograms?
According to the National Cancer Institute:
A screening mammogram is an x-ray of the breast used to detect breast changes in women who have no signs of breast cancer. It usually involves two x-rays of each breast. Using a mammogram, it is possible to detect a tumor that cannot be felt.
A diagnostic mammogram is an x-ray of the breast used to diagnose unusual breast changes, such as: a lump, pain, nipple thickening or discharge, or a change in breast size or shape. More pictures are taken than during a screening mammogram.
A diagnostic mammogram is also used to evaluate abnormalities detected on a screening mammogram. It is a basic medical tool and is appropriate in the workup of breast changes, regardless of a woman's age.
The development of digital mammography provides electronic images of the breasts that can be enhanced by computer technology, stored on computers, and even transmitted electronically in situations where remote access to the mammogram is required.
How is mammography performed?
X-rays of the breast are different than those used for other parts of the body. The breast x-ray does not penetrate tissue as easily as the x-ray used for routine x-rays of other parts of the body. The breast is compressed by the mammogram equipment to spread the tissue apart. This allows for a lower dose of radiation. Compression of the breast may cause temporary discomfort, but is necessary to produce a good mammogram. The compression only lasts for a few seconds for each image of the breast. A breast health nurse or x-ray technologist usually takes the x-rays, but the resulting films are read and interpreted by a radiologist, who reports the results to your physician.
What conditions does a mammogram show?
Calcifications, tiny mineral deposits within the breast tissue. There are two categories of calcifications:
macrocalcifications - coarse calcium deposits that usually indicate degenerative changes in the breasts, such as:
microcalcifications - tiny (less than 1/50 of an inch) specks of calcium. When many microcalcifications are seen in one area, they are referred to as a cluster.
Masses, which may occur with or without associated calcifications, and may be due to different causes, including:
cyst - a non-cancerous collection of fluid in the breast. It cannot be diagnosed by physical exam alone or by mammography alone. Either breast ultrasound or aspiration with a needle is required. If a mass is not a cyst, then further imaging may be obtained.
benign breast conditions - masses can be monitored with periodic mammography, but others may require immediate or delayed biopsy.
Who should get a screening mammogram?
The following screening guidelines are for early detection of cancer in women who have no symptoms:
Experts have different recommendations for mammography. Currently, the U.S. Preventive Services Task Force (USPSTF) recommends screening every two years for women ages 50 to 74. The American Cancer Society (ACS) recommends yearly screening for all women ages 40 and older. Women should talk with their doctors about their personal risk factors before making a decision about when to start getting mammograms or how often they should get them.
The ACS recommends clinical breast exams (CBEs) at least every three years for all women in their 20s and 30s. The ACS recommends annual CBEs for women ages 40 and older. The USPSTF, however, believes there is not enough evidence to assess the value of CBEs for women ages 40 and older. Women should talk with their doctors about their personal risk factors and make a decision about whether they should have a CBE.
The USPSTF does not recommend breast self-exams (BSEs) because evidence suggests BSEs do not lower risk for death from breast cancer. The ACS says BSEs are an option for women 20 and older as a means of familiarizing themselves with their breasts so they can notice changes more easily. Talking with your doctor about the benefits and limitations can help you decide if you should start performing BSEs.
Women who are at an increased risk (family history, genetic tendency, past breast cancer) should talk with their physicians about the benefits and limitations of starting mammography screening earlier, having additional tests (breast ultrasound, MRI), or having more frequent exams.
National Cancer Institute Guideline for Screening Mammography
American Cancer Society Guideline for Screening Mammography
Women age 40 and older should have a screening mammogram on a regular basis, every one to two years.
Women 40 years of age and older should have a screening mammogram every year.
Consult your physician regarding your personal breast cancer risk and the screening guidelines that are appropriate for you.