Mammograms are a generally safe and mostly effective way to help detect breast cancer. Although they do expose people to small amounts of radiation, they typically will not cause harm unless the person experiences repeated exposure and long-term screenings.

This article reviews mammograms and their relationship to cancer. It also looks at other myths and facts related to mammograms.

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Mammograms are low-dose X-rays of the breast.

Exposure to radiation can increase the risk of developing cancer. The National Cancer Institute (NCI) notes that radiation exposure is a potential risk associated with mammograms. The risk is greatest when a person experiences exposure to repeated chest X-rays.

The researchers behind a 2016 study examined the effects of yearly or 2-yearly mammograms on women aged 40–74 years. They note that exposure to repeated mammography can increase the risk of developing breast cancer and that this risk may be higher for those with larger breasts. However, they also conclude that the benefits of screening outweigh the potential risks.

In addition, although mammograms do expose a person to radiation, the amount of radiation is equivalent to only 2 months worth of background radiation, which is within the current medical guidelines.

The Food and Drug Administration (FDA), Mammography Quality and Standards Act, and other agencies all play a role in regulating equipment and radiation exposure, which helps keep exposure levels within a safe range.

The NCI also notes that the benefits of early detection outweigh the potential risks associated with mammograms. Regular mammograms have helped reduce the total number of deaths due to breast cancer.

If a person is concerned about the risks involved, they can speak with a doctor.

According to, mammograms are safe.

The NCI, American Cancer Society (ACS),, and other agencies and organizations support regular mammogram screenings to help detect cancer. The amount of radiation exposure from a mammogram is lower than that of a standard X-ray and well within safe ranges for everyone.

In a practice bulletin from 2017, researchers note that mammograms are generally safe for average-risk people. However, they add that higher breast densities may cause other issues, including false positives, that can have other health effects, such as overtreating a growth that does not require treatment.

The main benefit of undergoing mammograms is that they can help detect breast cancer early.

According to the ACS, mammograms can find changes in the breast that could be cancer long before any physical symptoms appear. It notes that those who undergo regular mammograms:

  • are more likely to have breast cancer detected early
  • are less likely to require aggressive treatment, such as surgery
  • are more likely to have any cancer cured

Some potential risks and drawbacks associated with mammograms include:

  • False positives: These can occur when a radiologist notices an irregularity on the mammogram but no cancer is present. This can lead to anxiety and additional testing. False positives appear to be more common in younger people, those with dense breasts, individuals who have previously undergone breast biopsies, and people with a family history of breast cancer. They are also more common in those taking estrogen.
  • Overdiagnosis and treatment: The test could find noninvasive and nonthreatening tumors that do not need treatment. However, it is difficult for doctors to distinguish between cancers that require treatment and cancers that do not. As a result, doctors usually treat them all.
  • False negatives: These occur in about 20% of cases and can lead to delays in diagnosis and treatment.
  • Finding breast cancer early might not reduce the chance of a person dying: A fast-growing tumor may have already spread to other parts of the body. As a result, some people may live longer while knowing that they have a potentially fatal condition.

There are no specific guidelines on when a person should begin getting mammograms, and suggestions from different agencies can differ.

The United States Preventive Services Task Force suggests that those aged 50–74 years get screenings every 2 years. It also suggests that those aged 40–49 years speak with a doctor to discuss the benefits and risks of screening.

The 2016 study notes that the benefit-to-harm ratio could improve if people start getting screenings at age 50 years as opposed to age 40 years. It could also improve if screenings took place every other year for those aged 50–74 years.

However, it is important for a person to consider their personal risk factors, such as family history or genetics, when they and their doctor decide when to start undergoing mammograms.

Learn more about mammograms and age here.

There are a lot of myths and misconceptions about mammograms. The following are some of the more common myths that a person may read or hear.

Myth: Mammograms are guaranteed to find all early signs of breast cancer.

The reality is that no test is perfect.

In fact, mammograms can miss an average of 20% of cases. A person who is at risk should speak with a doctor if they have concerns that the mammogram may have missed something.

Myth: A person needs a referral for a mammogram.

Starting at age 40 years, a person can request a mammogram.

They do not need a prescription, recommendation, or any other referral from a primary care doctor. However, the person may want to discuss their medical history with a doctor and talk about when they should begin breast cancer screening.

Myth: A person does not need a screening every year if they have a normal test.

Many agencies, including the ACS, recommend annual screening for average-risk people aged 45–54 years regardless of whether the previous year’s test was negative.

If a test comes back with positive results, a person should speak with a doctor about the next steps for diagnosis.

Mammograms expose a person to small amounts of radiation. However, this exposure is limited and will not cause cancer unless the person has exposure to frequent testing.

The potential benefits of earlier detection outweigh the concerns of exposure as well as other issues, such as false positives.

A person should discuss their risk factors for breast cancer with a doctor and consider undergoing screening starting at the age of 40 years, 50 years, or sooner based on individual risk.