Breast Cancer Awareness Month: What is a mammogram, does it work and how often do you need it?

Regular mammograms are the best tests doctors have to be able to find breast cancer early, sometimes up to three years before it can be felt


                            Breast Cancer Awareness Month: What is a mammogram, does it work and how often do you need it?
(Getty Images)

Breast cancer screening refers to checking a woman's breasts for cancer before there are signs or symptoms of the disease. It cannot prevent breast cancer, but it can help detect breast cancer early when it is easier to treat. Every screening test has benefits and risks, which is why experts advise that it is important to talk to your doctor before getting any screening test. One such screening test is known as mammography that uses X-ray technology to view the breasts. A mammogram is an X-ray picture of the breast that doctors use to look for early signs of breast cancer. 

Not all organizations agree on breast cancer screening guidelines, and the guidelines themselves can be conflicting. But most health experts emphasize meeting with the doctor to review the risks, limitations and benefits of mammograms to determine what is right for a particular situation. Here's what the different guidelines say.

Women aged 40 to 49 years with average risk

US Preventive Services Task Force: The decision to do mammography in women before 50 years should be an individual one. 

American Cancer Society: Women aged 40 to 44 years should have the choice to start screening once a year with mammography if they wish to do so. Women aged 45 to 49 years should get mammograms annually.

American College of Obstetricians and Gynecologists: After counseling and if an individual wants screening, mammography may be offered once a year or once every two years.

American College of Radiology: Recommend once a year. 

American College of Physicians: Clinicians should discuss whether to do a mammogram before 50 by talking about the potential benefits and harms and a woman’s preferences. The potential harms outweigh the benefits in most women.

American Academy of Family Physicians: Decision should be an individual one. 

International Agency for Research on Cancer: Limited evidence that screening with mammography reduces breast cancer deaths in this age group.

Women aged 50 to 74 years with average risk

US Preventive Services Task Force: Recommends once every two years.

American Cancer Society: Annually for women aged 50 to 54 years. Women 55 and older should switch to mammograms every 2 years or can continue yearly screening

American College of Obstetricians and Gynecologists: Recommends once a year or once every two years.

American College of Radiology: Recommends once a year.

American College of Physicians and American Academy of Family Physicians: Both suggest once every two years

International Agency for Research on Cancer: Says there is sufficient evidence mammography reduce breast-cancer mortality to an extent that its benefits substantially outweigh the risk of radiation-induced cancer from mammography.

Every screening test has benefits and risks, which is why experts advise that it is important to talk to your doctor before getting any screening test, like a mammogram. (Getty Images)

Women aged 75 years or older with average risk

US Preventive Services Task Force: Current evidence is insufficient to assess the balance of benefits and harms of mammography in women 75 years or older

American Cancer Society: Women should continue screening with mammography as long as their overall health is good and they have a life expectancy of 10 years or more. 

American College of Obstetricians and Gynecologists: The decision to stop screening should include a discussion of the woman’s health status and longevity.

American College of Radiology: The age to stop screening with mammography should be based on each woman’s health status rather than an age-based determination.

American College of Physicians: Discontinue screening in average-risk women aged 75 years or older, or in women with a life expectancy of 10 years or less.

American Academy of Family Physicians: Current evidence is insufficient to assess the balance of benefits and harms.

International Agency for Research on Cancer: Not addressed

For high-risk women

Some organizations release different breast cancer screening guidelines for women who are considered to be at a high risk of developing breast cancer. Different screening guidelines may be suggested for women who have risk factors such as a BRCA1 or BRCA2 mutation, who are an untested family member of someone who has a BRCA1 or BRCA2 mutation, who have a history of mantle or chest radiation, which occurred before 30 years of age, or who have a lifetime breast cancer risk of 20% or greater based on their family history.

What to expect from a mammogram?

The person is asked to stand in front of a special X-ray machine while a technologist places the breast on a plastic plate. Another plate will firmly press the breast from above. The plates will flatten the breast, holding it still while the X-ray is being taken. The steps are repeated to get a side view of the breast. The other breast will be X-rayed in the same way. 

When are the results ready? 

The results are usually given within a few weeks, but it depends on the facility. A radiologist reads a person’s mammogram and then reports the results to the woman and her doctor. If there is a concern, one may hear from the mammography facility earlier. 

During a mammography, the breast is pressed between two plates and X-rays are used to take pictures of breast tissue. (Getty Images)

What are the benefits? 

For many women, mammograms are the best way to find breast cancer in its early stages, when it is easier to treat, and before it is big enough to feel or cause symptoms, according to the US Centers for Disease Control and Prevention (CDC). “Regular mammograms are the best tests doctors have to find breast cancer early, sometimes up to three years before it can be felt. Having regular mammograms can lower the risk of dying from breast cancer. At this time, a mammogram is the best way to find breast cancer for most women,” says the agency.

What are the risks?

Having a mammogram is uncomfortable for most women, and some women find it painful. However, a mammogram takes only a few moments, and the discomfort is over soon. Mammograms may also miss some cancers, called false-negative test results, which may delay finding cancer and getting treatment. Another potential harm is radiation exposure from the mammogram test itself. While the amount of radiation in a mammogram is small, there may be risks with having repeated X-rays.

What happens if the mammogram is normal?

As per guidelines, one can continue to get mammograms according to recommended time intervals. Mammograms work best when they can be compared with previous ones. This allows the radiologist to compare them to look for changes in breasts.

What happens if the mammogram is abnormal?

An abnormal mammogram does not always mean that there is cancer, but the person will need to have additional mammograms, tests or exams before the doctor can say for sure. The woman may also be referred to a breast specialist or a surgeon, but it does not necessarily mean the person has cancer or needs surgery. These doctors are experts in diagnosing breast problems, and they will do follow-up tests to diagnose breast cancer or to find that there is no cancer. For example, a screening mammogram may find a lump in the breast, which may be cancer or something else. More tests called diagnostic tests need to be done to find out if the lump is cancer. They may include a biopsy, in which cells or tissues are removed so a pathologist can check them under a microscope for signs of cancer.

Who to contact if you have questions?

Talk to your regular doctor, if you have one. You can find a mammography facility in your state or territory here. You can also contact the National Cancer Institute. The CDC's National Breast and Cervical Cancer Early Detection Program works with health departments and other groups to provide low-cost or free mammograms to women who qualify, and you can find out if you are eligible here

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