Screening Mammography
Dr Warwick Lee
A/Prof Liz Wylie
Date last modified: May 01, 2009
1. What is a Screening Mammography?
Screening mammography is a low-dose X-ray examination of a woman’s breasts. It is performed to detect breast cancer when it is too small to be felt as a lump. Screening mammography is performed on women who do not have any symptoms of breast disease. The aim of screening mammography is to reduce the death rate from breast cancer by detecting unsuspected breast cancers at an early stage. Early detection increases the likelihood of a cancer being successfully treated and often allows for greater treatment options.
2. How do I prepare for a Screening Mammography?
No preparation is required for screening mammography. A screening mammogram with BreastScreen Australia and BreastScreen Atearoa (NZ) is available free of charge to women over 40 who have no breast symptoms and does not require a doctor’s referral.
If you have breast implants please let the hospital, clinic or radiology practice know so they can schedule a longer appointment. This is because with the presence of implants, it takes more time to make sure clear images are taken.
Don’t wear any deodorant, perfume, lotion or talcum powder on the day of your appointment because these substances may show up as shadows on your mammogram. Wear a two piece outfit so you only need to undress from the waist up.
3. What happens during a Screening Mammography?
A mammogram image or picture is obtained using a special X-ray machine and placing the breast between 2 plates and compressing it (pressing it down). The mammogram and the compression are performed by a specially trained technician (called a radiographer or medical imaging technologist). The compression is uncomfortable and you may find the compression painful. However, the compression lasts only seconds and without having the compression, the X-rays will be blurry which makes it hard to see if a cancer is there. Compression also reduces the amount of radiation required for the mammogram.
4. Are there any after effects of a Screening Mammography?
There are usually no after effects of screening mammography. You may suffer redness or bruising from the compression but this only happens occasionally. Even if this occurs, the compression does not harm the breast.
5. How long does a Screening Mammography take?
A screening mammogram takes only 10-15 minutes to perform, including the time for the radiographer to check that the X-rays are of satisfactory quality. Sometimes, an X-ray needs to be repeated if the image is not clear enough. You do not have to wait for the mammograms to be read as these are read later and a report on the examination prepared and posted out to you.
6. What are the risks of a Screening Mammography?
Breast cancer screening in Australia has been shown to detect 90% of cancers in women who participate in the screening program. All women need to be aware that if they have a new or changing breast symptom (for example: a new or changing lump, discharge from the nipple, and skin puckering) they should seek prompt medical attention. This also applies even if they have had a normal mammogram recently as not all cancers are detected by mammography.
The risk that the radiation from a mammogram may cause breast cancer is extremely low, especially with the use of low-dose mammography. Such risk is far outweighed by the benefit of early detection of breast cancer, significantly reducing the death rate from the disease.
The Health Protection Agency of the United Kingdom estimates the risk of an additional cancer in a life time from a single mammographic examination to be in the low risk range: 1 in 100,000 to 1 in 10,0001.
This is the same as the risk of developing a cancer as a result of exposure to the natural background radiation accumulated from the normal environment in 1 year.
If your mammogram is abnormal (shows anything unusual) you may require further tests but these do not necessarily mean a diagnosis of breast cancer. Approximately 5% of women who have a screening mammogram need further tests to clarify unusual findings on the mammogram images. These additional tests are usually further mammograms and / or breast ultrasound. However, some women may also need a needle biopsy to further clarify the finding. This is where a fine needle is inserted into the breast and a small piece of tissue is removed and tested for any abnormality. In unusual cases, an operation (surgical biopsy) is required to confirm whether or not cancer is present.
You may experience discomfort and anxiety because of these extra tests and if there are any medical complications. Please remember there is a significant life saving benefit in the early detection of breast cancer. Having further tests does not necessarily mean you have breast cancer.
7. What are the benefits of a Screening Mammography?
Screening mammography aims to reduce the death rate from breast cancer. Screening mammography detects cancer at a smaller size and an earlier stage than is possible without screening. Between 1990 and 2004 there was a 24.5% reduction in the death rate in all women with breast cancer2. This study relates to women who were screened for breast cancer as well as those who did not undergo screening. It is also as a result of early detection of breast cancer by both screening and improvements in treatment. However, the benefits of screening are shown to be significant.
Approximately 65% of all invasive breast cancers (that has spread into surrounding tissue) detected by the BreastScreen Australia Program are small cancers (less than 15mm diameter, ref: BreastScreen Australia Monitoring report 2004-2005).
Screening mammography may also detect breast cancer in its very early stages, before it has spread into surrounding breast tissue when it is called pre-invasive cancer or Ductal Carcinoma in-situ (DCIS). Prior to the introduction of screening mammography, DCIS formed approximately 5% of all breast cancers. It now forms approximately 20% of all breast cancers. This increased rate of pre-invasive breast cancer is a direct result of mammographic screening and leads to improvement in the survival rate from breast cancer.
8. Who does the Screening Mammography?
In Australia, Screening Mammography is most often conducted by BreastScreen Australia as part of a National Screening program which aims to screen all women in Australia between 50 and 69 years of age. The program is freely available to ALL women over 40 years of age. Since screening mammography tries to detect very small cancers that are difficult to see or feel, the pictures or images are read by at least 2 people with expertise in reading mammograms to check them thoroughly. This is usually done by a Breast Screen Radiologist, a specialist doctor with particular training in breast imaging. Screening mammography may also be performed by radiologists outside of the BreastScreen Australia program.
In New Zealand, Screening Mammography is most often conducted by BreastScreen Aotearoa and is targeted to women between the ages of 45 and 69 years. BreastScreen Aotearoa is conducted along similar lines to BreastScreen Australia.
10. Where is a Screening Mammography done?
Screening Mammography is provided free of charge by BreastScreen Australia Breast Centres throughout Australia. The nearest screening centre can be found by ringing 13 20 50.
BreastScreen Aotearoa provides screening mammography free of charge throughout New Zealand. The nearest Centre can be located and an appointment made by ringing 0800 270 200.
Screening mammography may also be provided at private radiology practices.
11. When can I expect the results of my Screening Mammography?
If you have your mammogram with BreastScreen Australia you should receive your results by post within 2 weeks of having your screening mammogram.
However, you may be part of the approximately 5% of women who need additional tests such as ultrasound or needle biopsy. This may require an additional visit to your BreastScreen centre. When this happens the results may take longer, but you should receive your results within 28 days of having your screening mammogram.
12. Further information about Screening Mammography:
Difference between screening mammograms and diagnostic mammograms
Screening mammography is designed for women who do not have any signs of a breast lump or any other symptom of breast disease. If you have a breast lump you should see your local doctor immediately to discuss and plan investigation of the lump. You may require special mammographic tests such as diagnostic mammography, a breast ultrasound and/or a needle biopsy to diagnose the possible presence of breast cancer. If you have any unusual signs or symptoms you need to have more detailed tests rather than the standard mammogram that forms part of general screening mammography.The most effective way to save lives from breast cancer is early detection and early treatment. You are urged to take advantage of the free screening mammography available from BreastScreen for women over the age of 40. You are also urged to see your doctor immediately if you find a breast lump or any other unusual breast symptom.
13. Useful websites and references for consumers about Screening Mammography:
- BreastScreen Australia
http://www.breastscreen.info.au
- Nation Breast and Ovarian Cancer Centre
http://www.nbocc.org.au/
- NSW Breast Cancer Institute
http://www.bci.org.au/
- BreastScreen Aotearoa - National Screening Unit, New Zealand
http://www.nsu.govt.nz/References:
- The Health Protection Agency of the United Kingdom
Information Booklet produced by NRPB, Chilton, Didcot, Oxon OX11 0RQ
http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1194947388410- Breast cancer in Australia: an overview, 2006. Australian Institute of Health and Welfare and National Breast Cancer Centre, October 2006