A mammogram is an X-ray picture of the breast. It uses a tiny amount of radiation to produce detailed images of the breast. Although mammograms cannot be used to diagnose breast cancer, they are a valuable tool to help detect the early signs of breast cancer before symptoms have developed. If a radiologist finds any potential signs of breast cancer in a mammogram, they will order more tests to confirm the diagnosis.
Here is what you need to know about the use of mammograms to detect breast cancer, including what they involve and how to prepare for this test.
Mammograms are often one of the most important breast cancer screening tests. There are two general types of mammograms, based on their purpose: screening mammograms and diagnostic mammograms. A newer type of mammogram, known as a 3D mammogram, can also be used to produce detailed images of the breast tissue.
Regular screening mammograms can be used to identify the early signs of breast cancer (pre-cancer), sometimes years before someone has any apparent symptoms. These X-rays can often detect breast cancer long before a lump can be palpated (felt) through a breast self-exam or a clinical breast exam. Early detection gives doctors the chance to diagnose and treat cancer before it spreads.
Aside from cancer and pre-cancer, screening mammograms can also detect benign (non-cancerous) tumors and cysts, including the two most common types of changes found on a mammogram: masses and calcifications.
Most cancer organizations recommend annual mammograms for individuals over 40 or 50 years of age. Those with a genetic predisposition to breast cancer, a family history of breast cancer, or other specific risk factors will most likely require additional testing, such as breast magnetic resonance imaging.
Diagnostic mammograms are used if a screening mammogram indicates abnormalities or changes to the breast tissue. Diagnostic mammograms may also be used if radiologists find signs of potential breast cancer and need to check the tissue further. These X-rays use special techniques to provide a more detailed picture of the breast, as well as more images of the breast tissue.
A newer type of mammogram is called a 3D mammogram. It is also known as digital breast tomosynthesis or breast tomosynthesis. In a 3D mammogram, each breast is compressed once. A machine takes multiple low-dose X-rays, moving in an arc over each breast. This type of imaging allows doctors to see the breast tissues much more clearly and in three dimensions.
Multiple studies have suggested that 3D mammography lessens the chance of needing follow-up testing. More breast cancers appear to be found when this technique is used, and several studies show 3D mammography may be helpful for people with higher breast density.
Mammograms are used to detect abnormalities in the breast tissue. They can be used for the early detection of signs of breast cancer and further investigation of changes to the breasts.
Screening mammography is used for the detection of breast cancer in those who have no known breast problems or symptoms. Early detection can lead to early treatment, which may lead to better outcomes for individuals who are diagnosed with breast cancer.
Mammography alone cannot determine whether any abnormalities in the breasts are cancerous or provide a breast cancer diagnosis. If there is significant suspicion of breast cancer based on the mammogram results, a small sample of breast tissue may be removed for lab analysis (breast biopsy).
Mammogram of a normal breast (left). Mammogram of a breast with cancer, indicated by an arrow (right). (NCI)
Diagnostic mammograms provide additional images of the breast(s) that aren’t included in screening mammograms. These tests can be used if an abnormality — such as pain or nipple discharge — or a mass (lump) is found during a breast self-exam or clinical breast exam. These mammograms can also be used if someone is experiencing other symptoms of breast cancer.
If you are told you have an abnormal mammogram test result, it doesn’t necessarily mean you have cancer. An abnormal mammogram just means that your radiologist has found a change or abnormality that should be investigated with further testing. Mammograms alone cannot diagnose breast cancer.
Mammography has been in use for approximately 30 years. Recently, technological advancements have considerably improved the results and techniques used in mammograms. Mammograms today produce high-quality images of the breasts with X-rays that are low in radiation. However, there are some things to consider before choosing to undergo mammography.
Ask your doctor about the radiation used in mammography — particularly, whether exposure to this level of radiation poses a risk to you, given your overall health. Keep a record of your previous history of exposure to radiation, including other X-rays and radiographic scans, so your doctor will have a better idea of the risks you may face.
Overall, the radiation risks associated with mammography have been assessed as negligible. But if you are pregnant or think you might be, tell your doctor. Exposure to radiation while pregnant can lead to birth defects. If you’re pregnant and you must have a mammogram, you and your doctor can take special precautions to minimize radiation exposure to the fetus.
False-positive results occur when a radiologist mistakenly believes a benign growth or abnormality to be cancerous. These results may lead to further tests and procedures, such as repeated X-rays, breast ultrasounds, breast biopsy, radiation therapy, or surgery. These tests and procedures can cause anxiety and be invasive, expensive, and time-consuming.
As with false-positive results, radiologists can miss certain types of breast cancer. These are called false-negative test results. A false-negative result may delay the detection and treatment of breast cancer.
Different cancer research institutions offer different breast cancer screening guidelines. When it comes to people under 50 years of age at average risk of breast cancer, most organizations state that it’s up to the individual to decide if the potential benefits of getting a mammogram outweigh any risks.
Individuals with an increased risk or high risk of breast cancer are generally given a separate set of screening guidelines. Those with mutations to the BRCA1 or BRCA2 genes, those who have a 20 percent or greater lifetime breast cancer risk due to family history, or those who had chest or mantle radiation before the age of 30 should discuss with their doctor the best time to start mammograms.
It is important to undergo regular mammography as recommended by your doctor based on your age and breast cancer risk. Having regular mammograms allows your doctor to create a history of your breasts over the years. A radiologist can compare each past mammogram to current ones to look for any suspicious changes, which can help them detect breast cancer as early as possible.
If you are 40 years of age or older, have a family history of breast cancer, or have a genetic predisposition for breast cancer, your health care provider will likely notify you when it is time for a mammogram and refer you to mammography facilities.
When you schedule your appointment, be sure to inform the office that it is your first mammogram and ask what you need to know to be prepared for the appointment.
Certain factors can affect the results of a mammogram. For instance, wearing creams, lotions, deodorant, or talcum powder on the breasts or under the arms can interfere with the images produced. Having dense breast tissue — a risk factor for breast cancer — can also make it more difficult for radiologists to read the results of a mammogram.
Breast implants can also hide some of the breast tissue and obscure mammography images. Make sure to inform the radiology office of any breast implants before your appointment. They will be able to assign you a technologist who has experience performing mammograms on people with implants.
Ask how you’ll receive your results and approximately how long it will take. Your radiologist is also there to help you understand the results of your mammography if you have any questions.
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Do you have any tips for people undergoing their first screening or diagnostic mammogram? Share your experiences and thoughts in the comments below or by posting on MyBCTeam.