NHS Breast Screening Programme, England 2020-21

This is a National Statistics Publication

The United Kingdom Statistics Authority has designated these statistics as National Statistics, in accordance with the Statistics Registration Service Act 2007 and signifying compliance with the Code of Practice for Statistics.

Designation can be broadly interpreted to mean that the statistics:

• meet identified user needs;
• are well explained and readily accessible;
• are produced according to sound methods; and
• are managed impartially and objectively in the public interest.

Once statistics have been designated as National Statistics it is a statutory requirement that the Code of Practice shall continue to be observed.

Find out more about the Code of Practice for Statistics.

The statistics in this report are used to inform policy and to monitor the quality and effectiveness of screening services.

They are derived from information that is routinely collected by the NHS breast screening services for the operation of the screening programme, including quality assurance and performance management purposes.

Overview

Introduction

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.

Data sources

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).

The results

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).

Further investigation

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.

Higher-risk women

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.

Coverage

Defined as the percentage of women in the population who are eligible for screening at a particular point in time (31 March in the reporting year), who have had a test with a recorded result at least once within the screening round, i.e. in the previous 3 years.

Women are eligible for screening if they are in the screening age range unless they are ceased due to having had a bilateral mastectomy.

Coverage is routinely reported only for the age range invited for screening; currently coverage is best assessed using the 53-<71 age group as women may be 1st called at any time between their 50th and 53rd birthdays ⁸.

National coverage is calculated from the KC63 central return dataset as follows:

KC63 data are calculated using data from BS Select and include all women currently registered with an NHS GP practice and others who are not registered with a GP practice but who are otherwise known to the NHS¹⁰.

The total number of women who are not registered with a GP or otherwise known to the NHS is unknown and it is therefore not possible to estimate how overall coverage rates might be affected by this group.

Coverage is reported by LA in this publication and is based on the postcode of residence for each woman in the eligible registered population. Some women who cannot be allocated to an LA are known to the NHS and are recorded on the BS Select system but not included in national figures in this report. These women account for a small proportion of the total resident population (less than 0.5% aged 53-<71 at 31 March 2020) and do not have a significant impact on the national coverage figures.

Coverage at primary care organisation (PCO) level, i.e. prior to 2013-14 was based on the eligible PCO responsible population.

Uptake

Defined as the percentage of women invited for routine screening in the year, who were screened adequately within 6 months of invitation.

The rate is calculated from the KC62 central return data set as follows:

The programme standard for uptake is based only on women invited for routine screening and excludes self / GP referrals and short term recalls.

Cancer detection rate

Defined as the number of women with cancer detected per 1,000 women screened.

The rate is calculated from the KC62 central return data set as follows:

Benign biopsy rate

Defined as the number of women who had surgery which resulted in a diagnosis of benign breast disease (i.e. not cancer) or no breast disease per 1,000 women screened.

The programme aims to minimise the number of unnecessary operative procedures and so benign biopsy rates should be low.

The rate is calculated as follows:

Non-operative diagnosis rate

Defined as the number of women diagnosed without the need for surgery as a percentage of all women with cancer.

The programme aims to ensure that the majority of cancers are diagnosed without the need for surgery.

The rate is calculated as follows:

The invasive and non-invasive non-operative diagnosis rates are calculated in the same way as above with the following conditions:

• Invasive applies only to women diagnosed with invasive breast cancer as a percentage of all women diagnosed with invasive breast cancer.
• Non-invasive applies only to women diagnosed with non-invasive cancer (including definitely micro-invasive and possibly micro-invasive) as a percentage of all women diagnosed with non-invasive cancer.

Assessment rate

Defined as the percentage of women screened who were referred for assessment following their initial screen.

Women are referred to an assessment clinic for further tests if a potential abnormality is detected at initial screening.

The rate is calculated as follows:

Small cancer detection rate

Defined as the number of women with invasive cancers smaller than 15mm in diameter detected per 1,000 women screened.

The rate is calculated as follows:

Standardised detection ratio (SDR)

Defined as the ratio of the observed number of invasive cancers to the expected number of invasive cancers:

The expected figures are derived based on applying criteria from the Swedish Two County randomised controlled trial, which is used as a yardstick of performance. The expected figures are calculated as follows:

NB. Rates differ according to whether women were part of prevalent or incident screening.

The expected figures for each age group are calculated by applying the following rates (from the Swedish Two County study) to the number of women screened in each age band:

Prevalent screening refers to women being screened for the 1st time within the programme. In this publication, prevalent screening figures relate to 1st invitations for routine screening and routine invitations to previous non-attendees.

Incident screening refers to women previously screened within the programme. From 2020-21 onwards, incident screening figures include both those with a previous screening within the last 5 years and those previously screened more than 5 years ago.

Invitation type

1st invitation for routine screening

Women invited to attend for routine breast screening with:

• no previous invitation for NHS breast screening

and

• no previous adequate screen within the programme as a self or GP referral

Routine invitation to previous non-attenders

Women invited to attend for routine breast screening with:

• 1 or more previous invitations for NHS breast screening

and

• no previous technically adequate screen within the programme

Routine invitation to previous attenders (last screen within 5 years)

Women invited to attend for routine breast screening with:

• any number of previous invitations for NHS breast screening

and

• at least 1 previous adequate screen within the programme as a result of an invitation or a self or GP referral within the last 5 years (60 months)

Routine invitation to previous attenders (last screen more than 5 years previously)

Women invited to attend for routine breast screening with:

• any number of previous invitations for NHS breast screening

and

• at least 1 previous adequate screen within the programme as a result of an invitation or a self or GP referral, the most recent of which was more than 5 years (60 months) ago

Short term recalls

Women invited to attend for non-routine breast screening with:

• any number of previous invitations for NHS breast screening

and

• a previous adequate screen within the programme as a result of an invitation or a self or GP referred episode within the last 3 years (36 months)

and

• the previous episode resulted in a recommendation for non-routine recall A non-routine recall is an intentional recall after less than the normal recall interval of 3 years (or other recall period followed by the programme).

Referral type

Self or GP referrals of women not previously screened

Women who attended for routine breast screening as a result of a self or GP referral with:

• any number of previous invitations for NHS breast screening

and

• no previous technically adequate screen within the programme

Self or GP referrals of women previously screened (Last screen within 5 years)

Women who attended for routine breast screening as a result of a self or GP referral with:

• any number of previous invitations for NHS breast screening

and

• at least 1 previous technically adequate screen within the programme as a result of an invitation or a self / GP referral within the last 5 years (60 months)

Self or GP referrals of women previously screened (Last screen more than 5 years previously)

This includes those women who attended for routine breast screening as a result of a self or GP referral with:

• any number of previous invitations for NHS breast screening

and

• at least 1 previous technically adequate screen within the programme as a result of an invitation or a self/GP referral, the most recent of which was more than 5 years (60 months) ago

See Appendix G for details of how the COVID-19 pandemic affected the programme in 2020-21.

Risk category

Genetic/familial risk

Women with a strong family history of breast cancer are likely to have inherited a faulty gene or genes that predispose to breast cancer from 1 or other of their parents. Screening is undertaken for women at higher-risk who have or are likely to have inherited a high-risk fault in 1 of these genes.

Breast cancer gene 1 (BRCA1) or Breast cancer gene 2 BRCA2

The function of the BRCA genes is to repair cell damage and keep breast, ovarian, and other cells growing normally. When these genes contain mutations that are passed from generation to generation, the genes don't function normally and the risk of breast, ovarian, and other cancer increases.

TP53 (Li-Fraumeni)

Inheriting a TP53 mutation causes Li-Fraumeni syndrome, a disorder that causes people to develop soft tissue cancers at a young age. People with this rare syndrome have a higher-than average-risk of breast cancer and several other cancers.

Ataxia-telangiectasia (A-T) gene mutation (ATM) - homozygotes or heterozygotes

The ATM gene helps repair damaged deoxyribonucleic acid (DNA). Inheriting 2 mutated copies of this gene (homozygotes) causes the disease ataxia-telangiectasia, a rare disease that affects brain development. Inheriting 1 mutated ATM gene (heterozygotes) has been linked to an increased rate of breast cancer and pancreatic cancer in some families because the mutation stops the cells from repairing damaged DNA.

Not tested, equivalent high-risk

A strong family history that makes inheriting 1 of the known high risk genes likely, but for a variety of reasons genetic testing has not been undertaken. Defined by a geneticist.

Supradiaphragmatic radiotherapy – irradiated below age 30

Radiotherapy administered in the area of the chest to women under the age of 30 for the treatment of Hodgkin's lymphoma¹¹, a cancer of the lymphatic system. This treatment increases the risk of breast cancer.

The categories 'Radiotherapy aged 10-19' and 'Radiotherapy aged 20-29' reflect new screening protocols that were introduced part way through 2020-21.  The majority of activity in 2020-21 was recorded under the category 'Radiotherapy below age 30'.

In 2020-21, data is now available for the following risk categories:

• CDH1
• PALB2
• PTEN Hamartoma tumour syndrome
• STK11
• Other high-risk gene

This section details known users of the report and the purposes for which they use the statistics. All these users have found the information in the report useful for the purposes set out.

Department of Health and Social Care (DHSC)

The DHSC use the statistics to inform policy and to monitor the quality of screening services. They are also used to respond to public and Parliamentary business.

NHS England and NHS Improvement

The NHS breast screening programme team (Public Health Commissioning and Operations) within NHS England and NHS Improvement use the report as a reference document to monitor the quality and effectiveness of the NHS Breast Screening Programme and progress against their key targets for screening the eligible population in England with the NHSEI regional public health commissioning teams.

NHS England and Improvement also use the statistics to monitor the quality of screening services commissioned against standards set out in the Section 7a Annual Public Health Functions Agreement with the DHSC.

Screening Quality Assurance Advisors (SQAAs)

The Regional Senior Quality Assurance Advisors use the report as part of their role in ensuring the screening process is safe and achieving its primary targets across England.

Breast screening units (BSUs)

BSUs use the statistics for planning and performance monitoring purposes.

Policy Research Unit in Cancer Awareness, Screening and Early Diagnosis

The Policy Research Unit carries out research on changes to the screening programme and the effects of such changes on markers of screening quality, such as detection rates and recall rates.

Organisation for Economic Co-operation and Development (OECD)

The screening statistics are supplied to the OECD by NHS Digital and are used in the OECD Health Database. They are also used for the Health Care Quality Indicator project.

Compendium of Population Health Indicators

Indicators from the publication are included in the Compendium of Population Health Indicators which is widely used within the NHS as well as outside it. See: 

National Audit Office (NAO)

Outcome statistics for prevalent and incident screens were used to inform the NAO report, Healthcare across the UK. This report highlights key trends and variations in the delivery of healthcare across the 4 countries of the UK.

Media

The data are used to underpin articles in newspapers, journals, etc. on matters of public interest.

Local authorities

LAs and NHS Clinical Commissioning Groups (CCGs) are required to prepare Joint Strategic Needs Assessments of Health and Wellbeing (JSNAs), which inform local commissioning of health and wellbeing services. Indicators from the publication form part of the Local Government Association’s Joint Strategic Needs Assessment: Data Inventory (via the Compendium of Population Health Indicators).

Unknown users

The breast screening publication is free to access via the NHS Digital website and therefore the majority of users will access the report without being known to NHS Digital.

It is important to put mechanisms in place to try to understand how these additional users are using the statistics and also to gain feedback on how we can make the data more useful to them.

Feedback on this publication can be sent to the following e-mail address: enquiries@nhsdigital.nhs.uk

Feedback on the following themes would be particularly useful:

• How useful did you find the content in this publication?
• How did you find out about this publication?
• What type of organisation do you work for?
• What did you use the report for?
• What information was the most useful?
• Were you happy with the data quality?
• To help us improve our publications, what changes would you like to see (for instance content or timing)?
• Would you like to take part in future consultations on our publications?

All feedback is passed to the team responsible for the report to consider.

NHS Digital publishes around 90 series of official statistics and National Statistics each year. Use of health and care statistics helps those involved to manage the system more effectively, commission better services, understand public health trends in more detail, develop new treatments and monitor the safety and effectiveness of care providers.

In our 2016 consultation on changes to statistics produced by NHS Digital, we proposed a series of changes which will help us to better prioritise resources from our stretched budget while developing our statistical products to better meet the needs of our users. 

To date, changes to the main publication include greater use of visuals, such as infographics and dashboards, and simplifying the content and layout of documents for users.

Some responses also highlighted the need to publish timely data at a more granular level, i.e. CCG/GP Practice level, in addition to LA level, as this will support the needs of commissioners.

The responses also highlighted the need to retain the annual data tables as these are regarded as crucial for performance monitoring, benchmarking and trend analysis, as well as contributing to JSNA updates.

We continue to work with colleagues at NHS E to ensure publications remain relevant and explore potential future improvements.

The NHS Breast Screening Programme was seriously impacted by disruption from the COVID-19 pandemic during 2020-21

• In March 2020, all 78 NHS Breast Screening Units (BSUs) made their own decision to pause screening for approximately 3 months (March-June 2020) in order to allow staff to be redeployed to respond to COVID-19, and to protect patients and staff from the virus
• In April 2020 NHS England and NHS Improvement (NHSEI) issued a system wide letter which set out that local NHS systems and organisations should fully step up non-COVID key services as soon as possible. Screening and immunisation services were listed as critical services as priority screening services needed to continue to be available for the recognised highest risk groups
• Most services continued with, or restarted screening very high-risk women by mid-April 2020 and all BSUs recommenced screening activity between April and September 2020 with the majority restarted by July 2020
• Routine screening for the total eligible population commenced across services in June/July 2020, resulting in backlogs of women waiting to be invited for screening and across the pathway​​
• COVID-19 restrictions (social distancing & additional infection prevention and control measures) impacted on lengthened appointment times and increased time between screening invitations. Workforce sickness/self-isolation and redeployment was also an issue.​​
• Fewer women presented for breast screening; contributory factors may have included shielding and self-isolation.
• Local variations in screening uptake were impacted by the geographical variation in COVID-19 incidence and in local restrictions throughout the year. 

NHSEI, supported by Public Health England, led a comprehensive restoration programme to support BSUs to restore all services

To maximise screening capacity and aid the restoration of screening:

• recruitment to the AgeX Trial was ceased in March 2020 enabling resources & capacity allocated to the trial to be utilised for restoration efforts
• the screening of self-referrals aged 71 or over, was suspended between April and October 2020 as an interim measure.  Women were advised to contact their GP if they were concerned about any symptoms
• open invitations were recommended rather than timed invitations in September 2020 to maximum utilisation of screening slots. Whilst open invitations may lead to lowered overall uptake in comparison to timed, there is a greater likelihood of attendance where a person has responded to an invitation to make an appointment than when they receive one with a fixed time, so maximising the likelihood of use of the limited capacity
• following an equality impact assessment undertaken by NHSEI, women with learning disabilities continued to be offered timed appointments throughout 2020/21
• regional commissioning teams and providers were asked to consider the needs of specific groups relevant to their locality, and the actions required to support them to engage with the screening programme, building upon existing work by cancer alliances, primary care networks and others.

Data collection and validation processes were completed as normal, therefore, the accuracy and reliability of the statistics published in this report are of a comparable standard to previous years.

1. Details from the NHS Breast Screening Programme.

2. More information on the trial can be found at AgeX Trial. 

3. This information is publicised in standard programmes results letters, over 70s leaflets and in other information leaflets such as the “Helping you Decide” document which is designed to allow women to make an informed decision on whether to attend screening or otherwise.

4.  Breast screening: clinical guidelines for screening assessment

5. Breast screening: very high risk women surveillance protocols

6. Screening frequency protocols. 

7. Breast screening After Radiotherapy Dataset

8. With the AgeX trial, some women will now be invited before the age of 50 or after the age of 70. It is expected that coverage will continue to be calculated for the 53-<71 age range until full rollout of the age expansion is completed.

9. A technically adequate screen is defined as one which gives sufficient detail to allow a decision to be made to refer for assessment or to return to a routine recall status.

10. A woman who is not registered with a GP may still be known to the NHS (e.g. through presentation at a breast screening unit or other hospital attendance).

11. NHS website 

12. UK Parliament.