What is Mammography?
Mammography is a specific type of imaging that uses a low-dose x-ray system to
examine breasts. A mammography exam, called a mammogram, is used to aid in the
diagnosis of breast diseases in women.
An x-ray (radiograph) is a painless medical test that helps physicians diagnose
and treat medical conditions. Radiography involves exposing a part of the body
to a small dose of ionizing radiation to produce pictures of the inside of the
body. X-rays are the oldest and most frequently used form of medical imaging.
What are some common uses of
Mammograms are used as a screening tool to detect early breast cancer in women
experiencing no symptoms and to detect and diagnose breast disease in women
experiencing symptoms such as a lump, pain or nipple discharge.
A screening mammogram is an
x-ray of the breast used to detect breast changes in women who have no signs or
symptoms of breast cancer. It usually involves two x-rays of each breast.
Mammograms make it possible to detect tumors that cannot be felt. Mammograms can
also find microcalcifications (tiny deposits of calcium in the breast) that
sometimes indicate the presence of breast cancer.
Recommendations for screening
Women age 40 and older should
have mammograms every 1 to 2 years.
Women who are at higher than average risk of breast cancer should talk with
their health care providers about whether to have mammograms before age 40 and
how often to have them.
The National Cancer Institute (NCI) adds that women who have had breast cancer
and those who are at increased risk due to a genetic history of breast cancer
should seek expert medical advice about whether they should begin screening
before age 40 and about the frequency of screening.
Diagnostic mammography is used
to evaluate a patient with abnormal clinical findings—such as a breast lump or
lumps—that have been found by the woman or her doctor. Diagnostic mammography
may also be done after an abnormal screening mammography in order to determine
the cause of the area of concern on the screening exam.
How should I prepare for a
Before scheduling a mammogram, it is recommended that you discuss any new
findings or problems in your breasts with your doctor. In addition, inform your
doctor of any prior surgeries, hormone use, and family or personal history of
Do not schedule your mammogram for the week before your period if your breasts
are usually tender during this time. The best time for a mammogram is one week
following your period. Always inform your doctor or x-ray technologist if there
is any possibility that you are pregnant.
Some other recommendations:
* Do not wear deodorant, talcum powder or lotion under your arms or on your
breasts on the day of the exam. These can appear on the mammogram as calcium
* Describe any breast symptoms or problems to the technologist performing the
* If possible, obtain prior mammograms and make them available to the
radiologist at the time of the current exam.
What are the factors that
place a woman at increased risk of breast cancer?
The risk of breast cancer increases gradually as a woman gets older. However,
the risk of developing breast cancer is not the same for all women. Research has
shown that the following factors increase a woman's chance of developing this
* Personal history of breast cancer—Women who have had breast cancer are more
likely to develop a second breast cancer.
* Family history—A woman's chance of developing breast cancer increases if her
mother, sister, and/or daughter have a history of breast cancer (especially if
they were diagnosed before age 50).
* Certain breast changes on biopsy—A diagnosis of atypical hyperplasia (a
noncancerous condition in which cells have abnormal features and are increased
in number) or lobular carcinoma in situ (LCIS) (abnormal cells found in the
lobules of the breast) increases a woman's risk of breast cancer. Women who have
had two or more breast biopsies for other benign conditions also have an
increased chance of developing breast cancer. This increased risk is due to the
condition that led to the biopsy, and not to the biopsy itself.
* Genetic alterations (changes)—Specific alterations in certain genes (BRCA1,
BRCA2, and others) increase the risk of breast cancer. These alterations are
rare; they are estimated to account for no more than 10 percent of all breast
* Reproductive and menstrual history —Women who began having periods before age
12 or went through menopause after age 55 are at an increased risk of developing
breast cancer. Women who have their first child after age 30 or who never have a
child are at an increased risk of developing breast cancer.
* Long-term use of menopausal hormone therapy—Women who use combination
estrogen-progestin menopausal hormone therapy for more than 5 years have an
increased chance of developing breast cancer.
* Breast density —Breasts appear dense on a mammogram if they contain many
glands and ligaments (called dense tissue), and do not have much fatty tissue.
Because breast cancers tend to develop in the dense tissue of the breast (not in
the fatty tissue), older women who have mostly dense tissue on a mammogram are
at an increased risk of breast cancer. Abnormalities in dense breasts can be
more difficult to detect on a mammogram.
* Radiation therapy ("x-ray therapy")—Women who had radiation therapy to the
chest (including the breasts) before age 30 are at an increased risk of
developing breast cancer throughout their lives. This includes women treated for
Hodgkin's disease. Studies show that the younger a woman was when she received
her treatment, the higher her risk of developing breast cancer later in life.
* Body weight—Studies have found that the chance of getting breast cancer after
menopause is higher in women who are overweight or obese.
* Physical activity level —Women who are physically inactive throughout life may
have an increased risk of breast cancer. Being active may help reduce risk by
preventing weight gain and obesity.
* Alcohol —Studies suggest that the more alcohol a woman drinks, the greater her
risk of breast cancer.
What are some of the
limitations of screening mammograms?
* Finding cancer does not always mean saving lives—Even though mammography can
detect tumors that cannot be felt, finding a small tumor does not always mean
that a woman's life will be saved. Mammography may not help a woman with a
fast-growing or aggressive cancer that has already spread to other parts of her
body before being detected.
* False negatives —False negatives occur when mammograms appear normal even
though breast cancer is present. Overall, mammograms miss up to 20 percent of
the breast cancers that are present at the time of screening. False negatives
occur more often in younger women than in older women because the dense breasts
of younger women make breast cancers more difficult to detect in mammograms. As
women age, their breasts usually become more fatty (and therefore less dense),
and breast cancers become easier to detect with screening mammograms.
* False positives —False positives occur when mammograms are read by a
radiologist as abnormal, but no cancer is actually present. All abnormal
mammograms should be followed up with additional testing (a diagnostic
mammogram, ultrasound, and/or biopsy) to determine if cancer is present. False
positives are more common in younger women, women who have had previous breast
biopsies, women with a family history of breast cancer, and women who are taking
estrogen (for example, hormone replacement therapy).
What is the best method of
detecting breast cancer as early as possible?
Getting a high-quality mammogram and having a clinical breast exam (an exam done
by a health care provider) on a regular basis are the most effective ways to
detect breast cancer early. Like any test, mammograms have both benefits and
limitations. For example, some cancers cannot be detected by a mammogram, but
may be found by breast examination.
Checking one's own breasts for lumps or other unusual changes is called
breast self-exam (BSE). Studies so far have not shown that
BSE alone reduces the number of deaths from breast cancer. BSE should not take
the place of routine clinical breast exams and mammograms.