BreastScreen SA has developed a series of Position Statements that clearly articulate BreastScreen SA's position on a range of issues.
- The use of thermography to detect breast cancer
- Radiation dose from screening mammograms
- Screening women aged 40-49 years
- Breast awareness and breast self-examination
- Digital Mammography
- Use of Magnetic Resonance Imaging (MRI) for screening
- Breast density and screening
- The Use of Computerised/Mechanical Breast Imaging
- Over-diagnosis from mammography screening
- Screening mammography and the use of thyroid shields
- Tomosynthesis (3D Mammography)
BreastScreen SA does not recommend the use of thermography for the early detection of breast cancer.
Breast thermography, also known as thermal breast imaging, is a technique that produces “heat pictures” of the breast, by measuring the temperature of the skin of the breast. The rationale for thermography in breast imaging is that the skin overlying a breast cancer can be warmer than that of surrounding areas.
There is a high level of consistency in the approach of numerous medical organizations from Australia and abroad in warning against the use of thermography for breast cancer detection. Many of these organizations have arrived at their positions through expert multidisciplinary review of the scientific evidence. 1-8
The following organisations support the use of mammography and do not support the use of thermography for breast cancer detection (valid as at May 2007):
- BreastScreen Australia
- National Breast Cancer Centre
- Royal College of Radiologists of Australia and New Zealand
- Australian Medical Association (no position on thermography to date)
- American Medical Association
- American Cancer Society
- Cancer Research UK
- Mayo Clinic, USA
- Australian Therapeutics Goods Administration
- Medicare Australia.
According to several reviews there is no current scientific evidence to support the use of thermography in the early detection of breast cancer or in the reduction of mortality from breast cancer. The results of thermography in various studies are inconsistent, but overall, thermography produces an abnormal result in too many women who do not have cancer, and it misses cancers that are known to be present in other women. Of the range of techniques in use for the detection of breast cancer, mammography is currently the only examination that is supported by objective and randomised clinical trials for screening and diagnosis.
- American Medical Association. Thermography Update H-175.988, vol. 2007: American Medical Association Website, 2007.
- American Cancer Society. Thermography (Thermal Imaging), vol. 2007: American Cancer Society Website, 2007
- Australian Medical Association. Position Statement on Breast Cancer Screening, vol. 2007: Australian Medical Association Website, 2007
- BreastScreen Australia. Statement on use of thermography to detect breast cancer, vol. 2007: Australian Government Department of Health and Aging Website, 2007
- Cancer Research UK. Thermography or "heat mapping": Cancer Research UK website, 2007
- National Breast Cancer Centre, Breast imaging, a guide for practice. National Breast Cancer Centre, 2002
- National Breast Cancer Centre. BreastScreen Australia Program Statement on the use of thermography to detect breast cancer, vol. 2007: National Breast Cancer Centre Website, 2007
- Society of Breast Imaging. Use of alternative imaging approaches to detect breast cancer, vol. 2007: Society of Breast Imaging Website, 2007
Current at October 2007
BreastScreen SA acknowledges that some women may be concerned about the radiation involved in having a screening mammogram and some may believe that it may actually cause cancer in the future.
The following information from BreastScreen Australia may assist women in deciding whether or not to participate in regular screening:
- Screening mammograms involve exposing women to a small amount of radiation
- The level of radiation women receive is low, similar to that from many X-rays people commonly have. The radiation dose is minimised by firmly compressing the breast for a few seconds
- However, for most women, the benefits of having regular screening mammograms outweigh any possible risk from radiation exposure. 1
BreastScreen SA radiographers are specially trained to ensure that they achieve the best quality mammograms at the lowest radiation dose possible. Firmly compressing the breast in the X-ray machine (for about 10 seconds) stops the breast from moving and blurring the picture. This also flattens the breast tissue, so that small changes are less likely to be hidden. Compressing the breast also means that only a low dose of radiation is needed to see through the flattened breast tissue.
The dedicated mammography equipment used at BreastScreen SA is well maintained and tested daily to ensure that the radiation dose to the client is kept to a minimum.
BreastScreen SA primarily recommends screening for women aged 50 to 69 without breast symptoms or problems. For women in this age group, the benefit of having a screening mammogram every two years to detect breast cancer early outweighs any possible radiation risk from the X-ray. Early detection of breast cancer increases the chances of successful treatment.
1. BreastScreen Australia National Information Statement Risks and Benefits of Breast Cancer Screening. Endorsed by the National Advisory Committee to BreastScreen Australia. February 2003.
Current at October 2007
BreastScreen SA provides free screening mammograms to asymptomatic women aged 40-49 years upon request, but does not actively recruit women in this age group to the screening program. There is insufficient evidence to conclude that screening the population of women under 50 years of age by mammography will reduce mortality from breast cancer. BreastScreen SA recruitment activities are focussed on asymptomatic women aged 50-69 years, for whom there is evidence that regular screening mammography will reduce mortality from breast cancer.
BreastScreen SA supports the following BreastScreen Australia Policy Statement 1 regarding the screening of women aged 40-49 years:
"At this point in time, the latest evidence does not justify a national mammographic screening program which would actively recruit women aged 40-49 years.
Mammographic screening is available to asymptomatic women aged 40-49 years through BreastScreen Australia should they request it, however, women in this age group are not actively recruited into the program.
This policy is based on the consideration of:
- currently available research evidence
- harms and benefits to women; and
- relative costs and benefits in undertaking a population-based screening approach." additional information 2
- Breast cancer screening is not as effective for women aged 40-49, compared to women aged 50-69. Mammograms are less accurate in women in their 40s so breast cancer screening is less effective at reducing the overall number of women in their 40s who die from breast cancer
- The tissue of younger women’s breasts is usually more dense than that of older women and can show up as white areas on the X-ray. Breast cancers also show up as white areas on X-rays. This makes breast cancer more difficult to detect in screening mammograms. This means that screening mammograms could be less accurate at finding breast cancer for women in their 40s compared to women aged 50-69.
Therefore, for women in their 40s compared to older women:
- it is less likely that breast cancers will be detected
- more women will be asked to come back for further tests when they don’t actually have cancer.
BreastScreen Australia is currently undertaking a review of the national program and will examine the international literature on the clinical benefits and cost effectiveness of screening women aged 40-49 years of age. It is anticipated that the review findings will be published in late 2008.
Until then, BreastScreen SA plans to continue to work within the BreastScreen Australia national policy framework, which states that asymptomatic women over the age of 40 are eligible for screening, but women aged 50-69 are primarily targeted.
- Extract from BreastScreen Australia website
- Extract from BreastScreen Australia National Information Statement Breast Cancer Screening for Women Aged 40 to 49. Endorsed by the National Advisory Committee to BreastScreen Australia. February 2003.
Current at October 2007
This position statement applies to asymptomatic women (ie women without breast symptoms or changes).
BreastScreen SA recommends that it is important for women to be aware of the look and feel of their breasts. If they notice a symptom, such as a lump or nipple discharge, or any other change in their breasts, they should contact their doctor promptly to arrange further investigation. They are also advised to ask their doctor for a physical examination of their breasts every year.
Research has not shown that routine, systematic breast self-examination - that is, monthly self-examination of the breasts that follows a set routine - is effective in reducing deaths from breast cancer. Thus, BreastScreen SA has adopted the breast awareness approach.
This position is consistent with those of BreastScreen Australia 1, the National Breast Cancer Centre 2, and The Cancer Council Australia 3.
- From BreastScreen Australia National Information Statement Facts about breast cancer screening. Endorsed by the National Advisory Committee to BreastScreen Australia. February 2003.
Current at October 2007
Digital mammography is replacing standard analogue mammography world‑wide. BreastScreen SA has introduced digital mammography to all its clinics including the dedicated Assessment Clinic located in Wayville.
What is Digital Mammography?
When used for breast cancer screening, digital mammography is comparable to analogue mammography in the screening target group of women aged 50 to 69.1,2There is recent evidence that for some groups of women, digital mammography has higher diagnostic accuracy than analogue mammography. These groups include women with dense breasts, women under 50 years of age and premenopausal women.1,2
The Rationale for Digital Mammography:
1. Diagnostic accuracy
When used for breast cancer screening, Digital Mammography is comparable to Analogue Mammography in the screening target group of women aged 50 to 69.1,2 There is recent evidence that for some groups of women, Digital Mammography has higher diagnostic accuracy than Analogue Mammography. These groups include women with dense breasts, women under 50 years of age and premenopausal women.1,2 Health, Safety and Welfare Benefits
There are considerable health, safety and welfare benefits offered by Digital Mammography for clients and staff. Digital Mammography uses low dose radiation to produce an image of the breast. Occupational health for radiographers and film loading staff is likely to improve, with the changes to work flow and design resulting from the use of Digital Mammography.3
2. Health, safety and welfare benefits
There are considerable health, safety and welfare benefits offered by digital mammography for clients and staff. Digital mammography uses low dose radiation to produce an image of the breast. Occupational health for radiographers and film loading staff is likely to improve, with the changes to work flow and design resulting from the use of digital mammography.3
3. Improved Productivity
Digital mammography makes more efficient use of radiographers’ time, potentially leading to productivity gains and reducing waiting times for screening appointments. The screening target group of women aged 50 to 69 is increasing at about 2-3% per annum in South Australia. Through the use of digital mammography BreastScreen SA now has the capacity to meet this increased demand for screening by SA women. The use of digital mammography will assist BreastScreen SA to provide more screening mammograms. This may in turn support the screening program to approach BreastScreen Australia’s National target of screening participation rates of 70% or greater among women aged 50 to 69.4
- Galen B, Staab E, Sullivan DC and Pisano ED. 2002. American College of Radiology Imaging Network: The digital mammography imaging screening trial - an update. Acad Radiol. 9:374-375.
- Pisano ED MD, Gatsonis C PhD, Hendrick E PhD, et al, for the Digital Mammographic Imaging Screening Trial (DMIST) Investigators Group 2005: Diagnostic Performance of Digital versus Film Mammography for Breast Cancer Screening; The New England Journal of Medicine, Vol 353:1773-1783, No 17.
- Daus C. 2004. Understanding workflow in the FFDM environment. Decisions in imaging economics. (Agfa supplement) 8-11.
- BreastScreen Australia National Accreditation Standards. Developed by the National Quality Management Committee of BreastScreen Australia. Endorsed July 2001; Revisions endorsed November 2004.
Current at August 2013
Magnetic Resonance Imaging (MRI) uses strong magnetic fields and radio waves to visualise the details of various tissues in the body. MRI does not use ionising radiation (X-rays). BreastScreen SA recognises breast MRI as a new and evolving technology that can be used in conjunction with mammography for breast cancer screening in women at high risk of developing breast cancer.
Recently, federal funding was made available through Medicare for the use of breast MRI as part of an organised surveillance program for women younger than 50 years who are at high risk of developing breast cancer but who currently have no breast symptoms or changes.
Women at high risk include those with a strong family history or personal history of breast cancer and women who have inherited genes which predispose them to developing breast cancer. There is some evidence that the addition of breast MRI to screening mammography improves the detection of breast cancer in women with these inherited genes.
The National Breast and Ovarian Cancer Centre conducted a systematic review of the medical literature in 2006. This review concluded that for asymptomatic women at high risk of developing breast cancer, MRI is almost twice as effective as mammography in identifying breast cancers. However, the review also found MRI is also likely to identify as suspicious, other non-cancerous conditions more frequently than mammography. This can lead to unnecessary worry and additional procedures, including biopsy.
Studies suggest that MRI may detect some early forms of breast cancer, including ductal carcinoma in situ (DCIS) and some cancers which have not spread to the lymph nodes. However, there is no evidence that cancers detected by MRI are smaller or less likely to grow and spread than those detectable by mammography. There is insufficient evidence at present to show whether breast cancer detection by MRI results in survival benefits for women at high risk of developing the disease.
Given the relative merits of screening mammography and MRI, these techniques are regarded as complementary, to be used as part of a multidisciplinary approach to cancer surveillance in women at high risk of developing breast cancer. The optimal management strategies for this group are still evolving, but it is important that women in high risk groups do not rely solely on breast MRI as their early detection strategy.
Breast MRI is not available at BreastScreen SA, but is available through other providers in South Australia. Medicare rebate for annual breast MRI for women at high risk for breast cancer. Women aged under 50 years with specified high risk factors for breast cancer are now eligible for a Medicare rebate for annual breast Magnetic Resonance Imaging (MRI). Eligibility criteria specified in Medicare Benefits Schedule item number 63464 are as follows:
MRI performed under the professional supervision of an eligible provider at an eligible location where the patient is referred by a specialist or by a consultant physician and where:
- a dedicated breast coil is used, and
- the request for scan identifies that the woman is asymptomatic and is less than 50 years of age, and
- the request for scan identifies either:
- that the patient is at high risk of developing breast cancer due to one of the following:
- Three or more first or second degree relatives on the same side of the family diagnosed with breast or ovarian cancer;
- Two or more first or second degree relatives on the same side of the family diagnosed with breast or ovarian cancer, including any of the following features:
- bilateral breast cancer
- onset of breast cancer before the age of 40 years
- onset of ovarian cancer before the age of 50 years
- breast and ovarian cancer in one relative
- Ashkenazi Jewish ancestry
- breast cancer in a male relative.
- One first or second degree relative diagnosed with breast cancer at age 45 years or younger, plus another first or second degree relative on the same side of the family with bone or soft tissue sarcoma at age 45 years or younger; or
- that genetic testing has identified the presence of a high risk breast cancer gene mutation.
- that the patient is at high risk of developing breast cancer due to one of the following:
All women are encouraged to be aware of the look and feel of their breasts and to report any breast symptoms or changes to their doctors. In consultation with their doctors, women in high risk groups should participate in an organised cancer surveillance program. This may include regular clinical breast examination, yearly screening mammography and other imaging techniques, including MRI.
A full bibliography is available on request. The list of scientific papers was too extensive to include on this page.
Current at May 2009
BreastScreen Australia is a population based screening program, which invites asymptomatic women aged 50 to 74 years to have biennial mammography screening. The program aims to maximise the benefits of early breast cancer detection while minimising potential harm to women.
On a mammogram, fatty tissue appears black while the remaining breast tissue appears white or ‘dense’. Women vary in the composition of their breast tissue, and the relative amount of non-fatty areas on a mammogram is referred to as breast density. Higher breast density is associated with an increased risk of breast cancer. Also, since cancers also appear as white areas on mammograms, high breast density may potentially hide some cancers, interfering with the interpretation of mammograms. Dense breasts are common and normal occurring in about one-third of women over 50 years of age.
Increased breast density is associated with an increased risk of breast cancer. Breast density also has an impact on screening mammography, as it can lead to a lower accuracy or ‘sensitivity’ for cancer detection. Despite this, mammography is the best breast cancer screening test in a population based screening program for asymptomatic women aged 50-74, even those with dense breasts.
Although women with dense breast tissue have an increased risk of breast cancer, the risk is less than having a first degree relative who is diagnosed with breast cancer before menopause (which doubles the risk), or carrying a gene mutation (where the risk is about ten times higher).
BreastScreen Australia recognises that in the future, breast density may have a role in determining the frequency and method of an individual’s breast screening. Further research is required to investigate what this role might be, prior to the establishment of any new approach. BreastScreen Australia supports such research, greater discussion, and public awareness of breast density.
BreastScreen Australia does not provide supplemental screening using other technologies for women with dense breasts. This is because there is no randomised controlled trial data that shows supplemental screening (such as MRI, ultrasound or tomosynthesis) saves additional lives for asymptomatic women with dense breasts and no other risk factors. Mammography continues to be the only population based screening tool that has been shown by randomised controlled trials to be effective in reducing mortality from breast cancer for women. The potential harms of providing supplemental screening for women with increased breast density include unnecessary and invasive procedures, additional false positive examinations, higher rates of benign breast biopsies, over-treatment, overdiagnosis and the associated psychological distress, and additional cost to both the woman and the health system. While there is some evidence that these technologies may detect malignancies not found with mammography, the benefit of any additional cancer detection within a population based screening program has not been shown to outweigh the harms.
Breast density can be measured in two ways, either by a radiologist (or screen reading breast physician) analysing an image of the breast to make an estimate of density, or by using commercially available computer software analysis to provide a score. Both methods have limitations when used to measure breast density in a population based screening program. When the same mammogram is interpreted by different radiologists or by the same radiologist on different occasions, differing density may be reported (inter and intra-observer variability). While computer software analysis can measure each mammogram, it has not yet been proven to consistently measure each woman’s breast density from one screening mammogram to the next. For women assessed as having dense breasts, receipt of inaccurate breast density information may create undue anxiety about their risk and worry that mammography may have missed a breast cancer. For women with fatty breasts (low breast density), it may convey a false sense of security.
The BreastScreen Australia program aims to provide women with accurate and useful information so that they can make informed decisions about their own breast health and their decision to participate in screening. Before BreastScreen Australia adopts a national protocol for breast density reporting, the method needs to be validated, reliable and evidence-based, with benefits outweighing the risks for the women participating in the program.
Having two-yearly screening mammograms through BreastScreen Australia is currently the most effective way to detect breast cancer early in asymptomatic women aged 50-74 in a population based screening program. It is also important for women to be aware of the normal look and feel of their breasts because breast cancer can develop at any time.
The Standing Committee on Screening recommends that, until such time that more evidence is available on how breast density should be best assessed and managed, and evidence supports clinical pathways for women, BreastScreen Australia should not routinely record breast density or provide supplemental screening for women with dense breasts.
Mammography remains the most effective screening test for asymptomatic women aged 50-74 for reducing deaths from breast cancer in a population based screening program.
For women at high risk based on their family history, individualised surveillance recommendations may apply.
Women who are concerned about their risk of developing breast cancer, or may have symptoms of breast cancer, or notice a change in their breasts should see their GP to discuss diagnostic or management options.
The Standing Committee on Screening will continue to evaluate any emerging evidence for breast density and provide up-to-date evidence based reliable information for Australian women.
- BreastScreen Australia Position Statement and references
- Breast density - information for consumers (PDF 491KB)
While BreastScreen SA respects every woman’s choice in decisions that concern her health, BreastScreen SA does not recommend the use of computerised/mechanical breast imaging as an alternative to mammographic screening for the early detection of breast cancer.
Computerised/mechanical breast imaging involves applying light mechanical pressure to the breast tissue by a hand-held probe, and recording the reaction to that pressure by sensors embedded in the probe. The technique records the different mechanical properties of tissues in the breast from the skin surface. It is important to note that this technique is not related to digital or analogue mammography or ultrasound.
There is very little peer reviewed medical literature available to validate computerised/mechanical breast imaging for clinical use. There are no randomised controlled trials completed to assess this technique against other, validated breast imaging methods, such as mammography.
Computerised/mechanical breast imaging does not have regulatory approval for use as a population-based screening test for breast cancer in Australia. Clinical decisions cannot be based on this technique, and findings require assessment by conventional, validated methods, such as mammography or breast ultrasound, for a definitive diagnosis.
Consumers should understand that the proven survival benefits of the early detection of breast cancer offered through regular participation in mainstream, accredited mammographic screening services do not apply to this technique. While the technique of computerised/mechanical breast imaging aims to improve a consumer’s breast awareness, it does not distinguish between normal and abnormal breast tissue. Furthermore, the use of computerised/mechanical breast imaging may lead to unnecessary investigations, including ultrasound imaging and biopsy of findings of no clinical significance.
Of the range of techniques in use for the detection of breast cancer, mammography is currently the only examination that is supported by objective and randomised clinical trials for screening and the early detection of breast cancer.
Free population-based mammographic screening, offered through BreastScreen Australia, is targeted primarily at asymptomatic women aged 50-69 years. Women from 40 years of age are eligible for screening at BreastScreen SA. It is recommended that all women be aware of the look and feel of their breasts. If they notice a symptom, such as a lump or nipple discharge, or any other change in their breasts, they should contact their doctor promptly to arrange further investigation.
Current at July 2010
National Breast and Ovarian Cancer Centre (NBOCC)
This position statement has been endorsed by Cancer Council Australia, Cancer Institute NSW, Clinical Oncological Society of Australia and the Screening Subcommittee of the Department of Health and Ageing.
Mammography screening significantly reduces death rates from breast cancer by enabling earlier and more effective treatment.
Most breast cancers found through screening are progressive and would become symptomatic within the women’s lifetime if left untreated. It is likely, however, that there is a sub-set that would be non-progressive or progress so slowly that they would not otherwise be found in a woman’s lifetime.
Estimates of the size of this sub-set vary widely and are dependent on study design and research assumptions. While a range of 5% to 13% of all breast carcinomas was cited in the first position statement of the National Breast and Ovarian Cancer Centre as a plausible estimate of levels of over-diagnosis, publications since then have provided such widely varying estimates that a summary pooled estimate cannot be derived with any confidence.
Research is underway, including molecular and genetic research, to find means of identifying cancers at minimal risk of progression.
Recently there have been media reports on an increased risk of thyroid cancer in women who have routine screening mammography without thyroid shields.
There is no scientific evidence to support an increased risk of thyroid cancer from routine screening mammography; hence thyroid shields are not routinely used in any breast screening service in Australia.
Screening mammograms use very low dose X-rays and the thyroid gland is not directly exposed to the X-ray beam used for the mammogram. An American report suggests that a mammogram gives a dose equivalent to 30 minutes exposure to natural background radiation1 (that is the dose of radiation all around us all the time).
Screening mammography specifically targets the breast area with very little radiation scattered to other organs. BreastScreen Radiography staff are thoroughly trained and are highly skilled at ensuring the least radiation dose to the breast is used to gain the necessary images. The radiographers are required to undertake continual quality assurance processes to ensure the on-going effectiveness and safety of screening mammograms and continually monitor the X-ray doses being used.
The use of a thyroid shield during a screening mammogram may interfere with positioning of the breast and therefore can potentially reduce image quality and affect accurate reading of the mammogram.
For these reasons, the use of a thyroid shield for routine screening mammography is not recommended. However thyroid shields are available at BreastScreen SA screening clinics if requested by clients.
Women are encouraged to continue routine screening mammography.
- The American College of Radiologists and Society of Breast Imaging Statement on Radiation Received to the Thyroid from Mammography April 4, 2011.
- BreastScreen WA: Thyroid Guard Statement, April 2011
- Whelan C, McLean D, Poulos A. Investigation of thyroid dose due to mammography Australian Radiology (1999), 43:307-310
- Schonfeld SJ, Lee C, Berrington de Gonzalez A. Medical Exposure to Radiation and Thyroid Cancer. Clinical Oncology (2011) 1-7
- BreastScreen NSW State Physicist Associate Professor Lee Collins, Westmead Hospital
- American Thyroid Association
- Radiology Magazine Today
Breast tomosynthesis (3D mammography) is a new digital mammography technology that is in the early stages of testing and clinical evaluation for its possible benefits in screening and assessment. Currently, BreastScreen Australia uses two-view digital mammography as the primary test to screen women for breast cancer.
Tomosynthesis uses a modified digital mammography unit to create 3D images. A number of low-dose images (usually 11-25) of a compressed breast are taken from different angles and then digitally reconstructed to create a 3D image. The radiation dose with tomosynthesis may be higher compared to two-view mammography, however the evidence remains unclear.
Preliminary study results suggest that tomosynthesis has the potential to decrease the number of women who are recalled for further tests (reduce recall rates) and possibly increase the detection of breast cancer (improve sensitivity). A number of small studies have shown favourable results when comparing tomosynthesis to digital mammography.
BreastScreen Australia is a population based screening program for well women, and robust evidence is required before tomosynthesis could be used as a routine screening tool. This is because the relative harms and benefits to well women of radiation dose, and the cost, efficiency and effectiveness of using this technology are as yet unclear. The results of further clinical trials are needed before the technology could be recommended for population screening.
At this time, two-view mammography continues to be the most effective population primary screening test for breast cancer. New technologies for breast cancer screening must meet the Australian criteria for population screening as outlined in the Population Based Screening Framework.
There is evidence that tomosynthesis can be of benefit in an assessment setting. There is less supporting evidence for the benefit of tomosynthesis as the screening test for population screening of well women. It is therefore important to wait for results from international and Australian clinical trials, before tomosynthesis is considered for routine screening use within BreastScreen Australia.
The Standing Committee on Screening recommends that, based on current evidence, the use of tomosynthesis as a screening technology in BreastScreen Australia be confined to clinical trial settings. Two-view mammography remains the most effective screening test at this time. Tomosynthesis can be of benefit in an assessment setting.
Endorsed by the Community Care and Population Health Principal Committee of the Australian Health Ministers’ Advisory Council on 13 November 2014