Breast Cancer Screening
About breast screening and mammograms
During breast screening, a radiographer uses a special X-ray, called a mammogram creates an image of the breast by passing X-rays through the breast tissue at a very low dose. The different ways in which X-rays pass through different types of tissue allows radiologists to see if there is any abnormal tissue in the breast, to take pictures of a woman’s breasts. Breast screening is always carried out by female staff.
Breast screening can detect small changes in breast tissue before they can be seen or felt. As a result, breast screening saves lives due to earlier detection and treatment of breast cancer.
Research has shown that breast screening can also be used to determine a woman’s breast density. Breast density refers to the amount of collagen and glandular tissue compared with fatty tissue in the breast. A woman has high breast density when there is more collagen and glandular tissue compared to fatty tissue in her breasts, and low breast density when there is more fatty tissue compared to glandular tissue and collagen. We know from large studies that women with high breast density are more likely to have an increased risk of breast cancer compared to women of a similar age with low breast density. However it is important to remember that an individual woman’s breast cancer risk is determined by a combination of many factors, of which breast density is one. Find out more about breast density as a risk factor.
As well as attending breast screening, women can increase their chances of catching breast cancer early by being breast aware and reporting any changes to their doctor. Learn about the signs and symptoms and sign up for monthly breast check reminders with our breast awareness quiz.
(For full information on breast screening, see the NHS Breast Screening Programme page)
Who is screened and when?
- Breast screening is free on the NHS in the UK and a government-funded scheme in the Republic of Ireland.
- In the UK, women aged between 50 and 70 are invited for screening every three years. This is being extended to women aged 47 to 73 in some areas of England.
- In Ireland, women aged 50 to 64 are invited every two years
- Women at high risk due to their family history or anyone who detects unusual changes to their breasts may be screened after being referred by their doctor.
Risks and limitations of breast screening
- Screening involves exposure to small amounts of radiation – although the risks here are very small.
- Sometimes mammograms detect a tumour that might not have caused any harm to the woman over their lifetime – this is called ‘over-diagnosis’, and is one of the main criticisms of breast screening programmes.
- Screening is able to detect breast cancer but it won’t prevent the disease, so it’s vital that people are breast aware, especially between screening appointments.
- Occasionally some patients are recalled because of unclear mammograms or for more tests.
Non-invasive breast cancer
- Breast screening can also detect some non-invasive conditions such as ductal carcinoma in situ (DCIS)
- DCIS is when cancerous changes develop within the breast ducts that do not break out into the surrounding tissue
- Most cases of DCIS are detected by screening, rather than self-examination or referral by a doctor
- It is difficult to estimate how often DCIS will develop into invasive breast cancer, but it is believed that if left untreated, DCIS will develop into invasive breast cancer in up to 50 per cent of cases
- For that reason doctors usually recommend that DCIS is treated as they cannot predict how they will develop.
Questions and answers about breast cancer screening
Will breast screening hurt?
It can be uncomfortable and feel awkward and some find it is painful but only for a few seconds.
Can I re-arrange my appointment date?
Yes, call the screening unit on your invitation letter to arrange an alternative date.
Can I still be screened after the upper age limit?
Screening is still available and free to over 70s in the UK (and those over 65 in the Republic of Ireland) - your doctor can arrange an appointment for you.
Why aren’t women under 50 routinely screened?
- Most cases of breast cancer occur in women over the age of 50
- Traditional (film) mammography isn’t as effective at spotting changes in younger women’s dense breast tissue
- Therefore currently only women under 50 at high risk due to their family history or those who find unusual changes are screened after being referred by their doctor
- However, with the introduction of digital mammography, screening is being extended to women aged 47 to 73 in some areas of England.
Where can I find out more about issues relating to breast screening?
- You may find the following pages useful:
- Ductal Carinoma in situ (DCIS)
- Genetic screening
- Breast Cancer Campaign's research into screening
- Read our Research Team blog on The Future of Breast Screening
Independent breast screening review
In October 2011, Cancer Research UK and the National Cancer Director set up an independent review of breast screening. It aimed to weigh-up the benefits and risks of breast screening.
The review concluded, in October 2012, that the UK breast screening programme does save lives, with about 1,300 breast cancer deaths prevented each year.
However, the review also concluded that the programme also results in over-diagnosis. Over-diagnosis is when breast tumours are detected by a mammogram that might not have caused any harm to women over their lifetime.
The review found that of the approximately 16,000 women diagnosed with breast cancer through screening each year, 4,000 of them are over-diagnosed.
This means that around 1 in 4 of women who are diagnosed with breast cancer through screening would never have had a problem from their breast cancer if they hadn’t been screened.
Our response to the independent breast screening review
Breast Cancer Campaign worked with the charities Breakthrough Breast Cancer and Breast Cancer Care to produce a joint response to the review:
“This independent review has provided much-needed clarity - screening can save lives. This is good news for women as they can now be assured that breast screening can be beneficial. However, some women who attend screening may be diagnosed and treated for a cancer that may not have caused them harm in their lifetime. To ensure women understand what this may mean for them it is important they have access to clear and balanced information on the pros and cons of breast screening. As the UK’s leading breast cancer charities we are supporting the work of an expert group looking at the information women receive when invited for their screening appointments and we call for this to be available as soon as possible. We encourage all women to attend their screening appointments."