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What Is A Mammogram And What Does It Do?

A mammogram is a low dose x-ray picture of the breast, which allows doctors to identify abnormalities or changes in the breast. Mammograms can help to find breast cancer early, when treatment is most likely to be successful.

There are two types of mammograms:

  • Screening mammogram: Cancer screening means checking the body for cancer before the person has any symptoms. Screening mammograms are used to find breast cancer in women who have no symptoms of breast cancer. This screening process can detect cancers which are too small to feel, which can be as small as a grain of rice. For women over 50, mammograms are the most effective way of identifying breast cancer at an early stage. The earlier breast cancer is diagnosed, the better the chance of survival.
  • Diagnostic mammograms: These are used to evaluate symptoms such as suspicious results found on a screening mammogram, or other clinical signs of breast cancer (such as new lump or nipple discharge). In a diagnostic mammogram, the radiographer (health professionals who perform imaging scans) can tailor the examination to the patient, for example, take extra images of the area of concern. Diagnostic mammograms can be used to help diagnose breast cancer.


The Importance Of Mammograms

What are the benefits of a mammogram?

There are several benefits to having a screening mammogram:

  • Increased chance at surviving breast cancer: Breast screening reduces deaths from breast cancer. A recent study showed that breast cancers detected by breast screening through BreastScreen (Australia’s national breast screening program) had a 54% to 63% lower risk of causing death compared to breast cancer diagnosed in women who have never been screened through BreastScreen. For every 1000 women who have a screening mammogram every two years from age 50 to age 74, around 8 deaths will be prevented.
  • Improved early detection: A screening mammogram can detect very small cancers, as small as a grain of rice, before any symptoms are felt or noticed by you or your doctor. For women over 50, a screening mammogram is the best method for early detection of breast cancer.
  • Improved treatment options if diagnosed: When breast cancer is found early, it is most likely to be small, and successfully treated. Other benefits of early detection include increased treatment options and improved quality of life.
  • Free through BreastScreen: Breast screening through BreastScreen is free and an appointment usually takes less than 30 minutes.

To make an informed decision about breast screening, women should also be aware of the potential risks and limitations of screening. Potential risks and limitations include:

  • Although screening mammograms are the most effective method of detecting breast cancer early in women over 50 years of age, it is not 100% accurate. In a small number of cases, a breast screen will look normal, even if cancer is present.
  • You may be called back for more tests if the screening mammogram indicates an abnormality that requires further investigation. Most people who are invited for more tests will not have breast cancer.
  • Having a mammogram means being exposed to a very small amount of radiation. However, current research indicates that current benefits of breast screening outweighs any possible risks from radiation. The amount of radiation from screening is about the same as exposure to 18 weeks of natural radiation in the environment. Modern mammography machines use the smallest amount of radiation possible while still obtaining a high-quality image.


When should you get your first mammogram?

In general, women aged 50-74 years are recommended to have a free screening mammogram every two years in Australia.

Women aged 40-49 years or 75 years and older are also eligible to receive free mammograms. In deciding whether to get a mammogram, women in these age groups are encouraged to speak with their doctor and should consider the potential benefits and risks of a screening mammogram for them.

For women at increased risk of breast cancer (such as women with strong family history or genetic predisposition), it is recommended that an individualised screening program be developed in consultation with her general practitioner (GP) and/or specialist, which may include other imaging tests.

Screening mammograms may also be recommended for transgender and gender diverse people, who have a unique set of factors that affect their breast cancer risk. If you are transgender or gender diverse, please speak with your GP about your personal risk factors and the need for screening.


How often do you need a mammogram?

In general, women aged 50-74 years are recommended to have a screening mammogram every two years. For women at high-risk of breast cancer, breast screening may begin at a younger age and/or more often, depending on their individualised screening program developed in consultation with medical practitioners. Transgender and gender diverse people are encouraged to speak with their doctor about their need for screening mammograms.


What is the difference between a mammogram and ultrasound?

Mammograms and ultrasounds are different imaging techniques used to examine inside the breast. To create an image of the inside of the breast, a mammogram uses low dose x-rays while an ultrasound uses sound waves. An ultrasound can help to determine whether a lump in the breast is filled with fluid (such as a cyst) or is solid. Because a solid lump may indicate breast cancer, further testing (such as a biopsy) may be recommended to determine if the lump is cancerous.

Depending on the woman’s age, an ultrasound may be used with or without a mammogram to help diagnose breast cancer.

When should you get a mammogram if you have a family history?

Since breast cancer is the most commonly diagnosed cancer in Australia, many people will have a relative diagnosed with breast cancer by chance. Only 5-10% of breast cancers can be explained by inherited gene fault (mutation).

If you are concerned that you have an increased risk of breast cancer, it is recommended that you speak with your doctor or local family cancer clinic. They will help you assess your breast cancer risk and develop an individualised screening and risk management plan as needed. If you are a woman who has never had breast cancer, you can also consider using iPrevent, an online tool developed by NBCF-funded researcher Professor Kelly-Anne Phillips, to determine your breast cancer risk. It will also provide advice on how on to reduce your risk, depending on your risk level.

Things You Should Know Before Your Mammogram Appointment

How is a mammogram performed?

During a mammogram, each breast is compressed between two X-ray plates one at a time. This helps to spread the breast tissue out to give maximum visibility, and to obtain the best image of the breast possible. For a screening mammogram, usually two X-ray pictures are taken of each breast, one from the side and one from the top. The breast compression only lasts a few seconds each time.


Do mammograms hurt?

Some people may feel some discomfort from the pressure of the mammogram equipment pressing on the breasts. However, the breast is only pressed for a few seconds and the discomfort should not be painful. Please speak with your radiographer if you feel any pain during your mammogram. She will work with you to ensure the process is as comfortable as possible. You can also ask them to stop the procedure at any time.


How long does a mammogram take?

The mammogram process itself will take just a few minutes. However, your screening appointment will usually last around 20-30 minutes.


What happens if you have a mammogram while pregnant?

Women who are pregnant are not eligible for a mammogram through BreastScreen Australia due to the potential radiation risks and potential harm to the unborn baby. In general, mammograms are not routinely performed on pregnant women who are not at an increased risk for breast cancer.

If you are pregnant or think you may be pregnant, and you are experiencing any potential symptoms of breast cancer, please speak to your doctor without delay.


What is the cost of a mammogram?

Screening mammograms provided through BreastScreen Australia are free. As this program is jointly funded by Commonwealth, state and territory governments, access to this free service is limited to people who are eligible for Medicare. Referral from your GP is not needed. However, it is recommended that you speak with you doctor before booking if you:

  • Have any noticed any new or unusual breast change – please speak to your doctor as soon as possible.
  • Are concerned that you have an increased risk of breast/ovarian cancer due to strong family. history or genetic predisposition
  • Have been diagnosed with breast cancer in the past 5 years.

Mammograms can also be provided to investigate new or unusual breast changes (known as a diagnostic mammogram) as needed following a referral from a GP or surgeon. These mammograms can be done at private radiology clinics, private breast clinics or public hospital radiology departments.  Although these diagnostic mammograms are often subsidised by Medicare, the patient may also need to pay additional out-of-pocket costs.

Reviewing Your Results

When and how do you get the results of a mammogram?

For a screening mammogram through BreastScreen, your breast screen images will be examined by two or more specially trained doctors. Your mammogram results will then be sent to you within 2 to 4 weeks after your screening. These will be sent via postal mail. In general, your results will outline one of the following:

  • Your breast screen results are normal: There is no evidence of breast cancer in your mammograms. About 90% of women will receive a normal result. You will usually be asked to return for your screening mammogram in two years.
  • You need to have further tests: An area on your mammogram looks abnormal and more tests are needed. These tests are called ‘assessments’. Depending on the initial mammogram results, tests may include a clinical breast examination, an ultrasound, or a biopsy. Most women who have assessment tests do not have breast cancer.

For a diagnostic mammogram, a report of your results will be sent to your GP or surgeon, usually within a few days.


What does breast cancer look like on a mammogram?

Like other x-ray images, mammograms appear in shades of black, grey and white. Breast cancer and some noncancerous (benign) breast conditions can appear white on a mammogram. Specialist doctors (radiologists) trained to interpret mammograms can identify any abnormal areas, masses or calcium deposits that may or may not indicate breast cancer.

Identifying these abnormalities on a mammogram does not necessarily mean that there is cancer present. However, sometimes further tests, such as a biopsy, are needed to be sure.

Mammograms are the most effective method of detecting breast cancer early, especially in women over 50. However, they are not 100% accurate. There is a small chance that the mammogram will appear normal when there is cancer present. Even if your breast screen result is normal, it is important to continue being aware of any breast changes between screening mammograms. If you notice any new or unusual breast changes, such as a new lump, please speak to your doctor as soon as possible.

Further Resources

There are many resources available containing further information on mammograms and what to expect before, during and after the screening. Below are some resources:


Breast screening clinics for different states in Australia

In addition to private mammogram providers, there are over 500 BreastScreen locations across Australia, including permanent screening centres, assessment clinics and mobile units.

Click on the links below to find out about breast screening centres in your state.