The Minister for Victorian Health, Jenny Mikakos, recently announced the implementation of six new 3D breast screening machines throughout the state.
They will be used to assess women who are reminded for further investigation when a standard 2D screening mammogram takes an unexpected thing.
This sophisticated technology is designed within the public system to assist women with breast cancer to receive accurate diagnosis in a timely manner, ensuring that they can start appropriate treatment as soon as possible.
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But there is a distinction to be made here. While this funding will provide 3D mammography machines to be used for further assessment when there may be a problem, there are already many 3D mammography machines operating across the private system, which are offered to women as a way of t for routine screening.
It is often accepted that medical technology is better than traditional technology. But when we talk about mammography for routine breast screening, maybe that is not the case.
While the evidence shows that 3D mammograms get more cases of breast cancer than the 2D version, many of the additional cancer perceived may be harmful. In these cases, their detection will not lead to unnecessary anxiety and treatment.
What is a mammogram?
A mammogram is an x-ray of the boobs that can be used to investigate breast symptoms such as lumps and pain. It can also be used to make screening, to get breast cancer early in healthy women with no symptoms.
The BreastScreen program in Australia asks women aged between 50 and 74 years of age to receive a screening mammogram every two years. All women over 40 are welcome to attend if they choose.
The BreastScreen program offers ordinary 2D digital mammals. During this standard mammogram, the breast is compressed, and two images of each breast are taken using a small dose of radiation.
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What does 3D mammogram do in a different way?
3D mammography, also known as breast tomosynthesis, has been introduced in the last decade.
It is not currently used for screening as part of the BreastScreen program, but is available in many private radiology practices throughout the country.
3D mammogram applies the same compression as a 2D button, but takes different images, such as thin “slices”.
The radiologist can scroll by collecting the images on a computer screen to get a 3D picture of the breast, which can be examined by layer, one millimeter at a time. The aim is to look at normal breast tissue layers to get hidden cancer.
Research has shown that 3D mammograms can take some cancers that are not seen on ordinary 2D mammals. The cancer detection rate of 3D mammography was about 1.4 times higher than in the case of 2D mammography.
The additional cancers were detected by small 3D mammograms and were not dispersed to the lymph glands; these are early cancers that are expected to have better survival rates.
Cancer can be difficult to see in lump tissue or acute breast compact, which is usually seen in women before the menopause. The 3D mammography appears to be very good at detecting cancer among women with complicated breast tissue, which could cause the increase in detection.
The possibility of over diagnosis and over diagnosis
Some cancers are inadequate or are slowly growing and will not cause clinical symptoms. It may be difficult to distinguish these cancers from early detected aggressive cancer. So, when they are found at a refined mammogram, they can be treated with surgery and radiotherapy, while not being able to improve survival.
When we talk about breast screening, we often state the rate of recall. This is the number of women asked to return for further testing, and possibly treatment, when initial screening shows something unusual.
The rate of recall is important because, we know for 2D mammography, about 80-90% of women who are recalled for assessment do not have cancer.
In these cases, recurrence can lead to concerns, risks and pain associated with biopsy and surgery, and costs for unnecessary procedures.
Earlier research found that the lower rate of recall for 3D mammography was 2D mammography, so there were fewer false positive studies or false alarms that introduced additional tests, biopsies and anxieties.
But this question has been submitted to new research in Australia, published in the Medical Journal of Australia. This study included over 10,000 women attending the BreastScreen center in Victoria to carry out routine screening. Some were invited to have a 3D mammogram, while others had a traditional 2D mammogram.
Again, the cancer detection rate was about 1.5 times higher for 3D mammography. However, the rate of recall was actually higher for 3D mammography compared to 2D – so more women were asked to return to extra work (mammogram, ultrasound and / or biopsy).
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Should I have a 3D mammogram?
Public health experts are currently discussing the issue of over diagnosis in breast screening. The extent of over-diagnosis in screening is not agreed, but is assumed to be somewhat.
In the 3D mammography studies, including the latest study in Australia, a higher proportion of cancer in the 3D groups were very small or “in situ” offenses that were less likely to cause injury than more aggressive cancers. This means that many additional cancers detected by 3D mammograms “over diagnosed” cancers could cause women to undergo unnecessary cancer treatment.
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BreastScreen is unlikely to introduce a 3D 3D mammography screening in the short term, based on current evidence.
But would you have a 3D mammogram through private radiology practice? Perhaps, if you have a compact breast tissue or you are starting screening in your 30s or 40s because of breast cancer family history.
For older women, 3D mammography may not have additional advantages over 2D. Each woman should consider the balance of potential benefits (early detection) and potential harm (over-diagnosis, over-condemnation and anxiety) before deciding on 3D screening mammograms compared to 2D.