A mammogram is an X-ray examination of the breast that is performed to detect breast cancer in its earliest stages, often before any signs or symptoms are present. Mammograms allow early detection of small tumors, which are easier to treat than larger, more developed ones. They can also detect ductal carcinoma in situ (DCIS), small abnormal growths in a breast's milk ducts. Early removal of these growths helps to reduce the risk of future problems.
Reasons for a Mammogram
A mammogram can show abnormalities in breast tissue long before they can be felt on clinical or self-examination. Mammograms are performed for both screening and diagnostic purposes.
Screenings involve producing images of both breasts in order to detect any tumors that cannot yet be felt under the skin. They can also detect calcium deposits that may, or may not, indicate breast cancer.
Diagnostic mammograms are performed after a lump or other sign of breast cancer has been detected, or after abnormalities have shown up on a previous mammogram. Diagnostic mammograms target a specific area of the breast, and provide more detailed images from many more angles than screening mammograms. Diagnostic mammograms are also useful in evaluating breast tissue that is unusually dense, or that is partially obscured by breast implants.
Both screening and diagnostic mammograms help diagnose breast diseases, lumps, cysts, and benign and malignant tumors.
Candidates for a Mammogram
It is recommended that women between the ages of 40 and 75 have mammograms annually. Patients with certain risk factors should be extra vigilant, and may be advised to have screenings when younger or older than usually recommended. Those risk factors include the following:
- Having a personal or family history of breast cancer
- Being of Ashkenazi Jewish descent
- Possessing breast cancer genes (BRCA1 and BRCA2)
- Having abnormal changes in the breast
- Having used hormone-replacement therapy for a prolonged period
- Having used alcohol excessively
- Having had radiation to the chest
- Having dense breast tissue
Men are also diagnosed with breast cancer, although much more rarely. Although only one percent of breast cancer patients are men, they should be checked if they have symptoms or a significant family history of the disease, especially if they are between 60 and 70 years old.
Preparing for a Mammogram
A woman should not schedule a mammogram the week before her period, because the breasts are usually tender at this time. She is instructed not to wear deodorant, powder or lotion on the day of the mammogram. A pregnant woman should not have a mammogram because of the danger of exposing the fetus to radiation.
The Mammogram Procedure
During a mammogram, the woman stands with her breast against the mammogram plate. The professional administering the test positions each breast so that is appropriately compressed; compression helps even out the thickness of the breast so that all breast tissue can be visualized, and also holds the breast still to minimize blurring caused by patient movement. The X-rays (containing a very low dose of radiation) are then taken, and the images produced are displayed on a computer screen for the radiologist to view and analyze.
The mammogram procedure is uncomfortable for most patients, particularly if their breasts are sensitive, but the test does not take long and is usually well-tolerated.
Results of a Mammogram
Although mammograms are extremely useful, and have saved countless lives, they are not foolproof. Both false positives and false negatives occur. It is also possible for women to be overtreated and unnecessarily exposed to cancer treatments that may have adverse effects.
False-negative results are also possible. It is estimated that mammograms used for screening miss about 20 percent of breast cancers. This is especially true in women with dense breasts, who tend to be younger. In such cases, women who require treatment do not receive it and their cancer progresses without medical intervention.
Risks of a Mammogram
A mammogram is considered safe for most women, including those with breast implants. Before having one, however, a woman should let her physician know if she is pregnant, or has any preexisting medical conditions.