Breast screening is a method of detecting breast cancer at a very early stage and is routinely offered to women aged 50 to their 71st birthday1. (Please note, some women are 1st invited for screening whilst they are still 49 but in the calendar year of their 50th birthday).
Women may be invited to attend screening by the NHS Breast Screening Programme1 (the programme) or may attend as a result of self or GP referral if they have not been screened within the last 3 years. Invitations for breast screening are sent out by breast screening units (BSUs) to eligible women.
- A self-referral is where a woman contacts the screening programme either without an invitation, or more than 6 months after their last invitation, requesting to be screened.
- A GP referral is the same as a self-referral except that the initial contact with the programme is made by the GP on behalf of the woman.
- Symptomatic referrals (i.e. where a woman is referred to a specialist breast clinic with recognised symptoms of breast cancer) are not part of the screening programme and so are not included in this publication.
Age extension trial
The programme undertook a randomised controlled trial (AgeX2 trial), extending the programme to women aged 47- 49 and 71-73. The trial started at pilot sites in 2009. (Please note, some women in the trial may receive their 1st invitation at 46 but in the calendar year of their 47th birthday). The trial stopped recruitment in March 2020.
In order to get a significant result from the trial, the programme will need to invite women in the extended age ranges for at least 2 more (3-year) screening rounds.
Women aged 71-73 in the control group are able to self-refer into the programme. Women aged 47-49 in the control group were able request to be screened until 2016.
Although no women over the age of 73 will be invited for screening, the programme encourages self / GP referrals from women aged 71 or over at 3-yearly intervals3.
The statistics are derived from information that is routinely collected by NHS Digital, and NHS England and NHS Improvement, for the operation of the programme, including for quality assurance and performance management purposes.
Information on the programme is supplied from the following NHS Digital central return data sets:
KC62 – Information on invitations, uptake and outcomes from all BSUs across England.
KC63 – Information on the population coverage of the programme from all upper tier local authorities (LA).
Further information on the underlying sources of information can be found in NHS Digital’s list of administrative sources.
Breast screening process
At the screening unit
Breast screening uses mammograms (low dose x-rays) which can detect small changes in breast tissue which may indicate cancers. All BSUs now use digital mammography which uses computer imaging.
In 2020-21, there were 78 BSUs in England, each can offer screening which is hospital based, mobile or in other convenient community locations (e.g. shopping centres).
Mammograms are examined and the results sent to both the woman and their GP within 2 weeks.
A woman may be asked to go to an assessment clinic for further tests if a potential abnormality is detected at initial screening.
Women will be sent another screening appointment if their mammograms need repeating (e.g. if the x-ray was not clear enough).
At an assessment clinic more tests are carried out following the triple assessment process4. These may include clinical examination and patient history, additional imaging and pathology (fine-needle aspiration cytology and/or core biopsy).
- Core biopsy may be carried out where some of the breast tissue is removed using a wide-bore needle for analysis.
- Fine-needle aspiration cytology is where samples of breast cells or fluid are drawn off through a very fine needle for laboratory analysis.
Where assessment clinic examinations do not give a definitive result, some women may need to go on for an open biopsy performed by a surgeon. This is a minor operation to take 1 or more samples of tissue under general anaesthetic.
In a small minority of cases a definitive diagnosis cannot be made following the assessment process. Where this occurs, women may be recalled for a further assessment at an interval shorter than the normal screening interval of 3 years (short term recalls).
Women at higher-risk
Some women are identified and assessed by a specialist in genetics or oncology as having a higher risk of developing breast cancer than women in the general population. Women at very high risk are eligible for screening in the NHS BSP5. This group only form part of the high-risk group defined by the National Institute for Health and Care Excellence (NICE).
The programme has started managing the surveillance of these very high-risk women according to specified protocols6. Higher-risk has been a part of the specification for commissioning breast cancer since 2013-14.
As a result of these protocols, a woman can be referred by a GP or another relevant professional group for genetic or oncology assessment where their medical or family history indicates a higher risk of developing breast cancer.
At genetic assessment which happens as a part of the Clinical Genetics Services, a full personal and family history is taken. For some women a blood sample may be taken to test for specific known genetic abnormalities.
Women identified as being at very high risk of developing breast cancer may then be referred to the local BSU for inclusion in high-risk screening, where they will have the opportunity to discuss the process and benefits with a healthcare professional.
Referrals into the programme should only be via:
- a genetics service
- an oncology service
- breast cancer after radiotherapy database (BARD)7
Whilst some high-risk screening is performed using mammograms, others are performed using a magnetic resonance imaging (MRI) scanner; a large tube surrounded by a strong magnetic field.
For an MRI, a small injection of liquid contrast is given to help different areas of the breast tissue become visible on the scans. A visit for this type of screening usually takes between half an hour and an hour.
Women at higher-risk of developing breast cancer are offered screening more regularly than those in the routine programme up until their 50th birthday (usually annually). After this, some women will remain in high-risk screening and some women will enter routine breast screening (i.e. every 3 years). The protocols for each risk category determine screening frequency.