Cervical Screening Programme, England - 2021-2022 [NS]

The statistics presented in this publication are derived from information that is routinely collected by NHSE/I to inform policy and to monitor the quality and effectiveness of screening services.

They are presented by Upper Tier Local Authority (LA), region, pathology laboratory and colposcopy clinic.

Information is collected on the following NHS Digital Korner Collection (KC) returns:

• KC53
  Information from the call and recall system, collected for all 152 LAs.
• KC61
  Information on screening samples tested by pathology laboratories, collected from all 8 laboratories carrying out cervical screening in 2021-22. . 
• KC65
  Information on referrals to colposcopy, subsequent treatment and outcomes, collected from all 191 clinics providing colposcopy services in 2021-22.

The full KC forms are available via the main publication page.

In addition to the KC returns, the following data is also collected:

• VSA15
  Data on time from screening to receipt of results, collected for all 152 LAs.
• PHOF¹
  Data on age-appropriate coverage², collected for all 152 LAs.

Further information on the underlying sources of information can be found in the separate appendices and in our list of administrative sources.

The data from each of the 3 KC returns are collected at the end of each financial year.

The KC53 data comes from the NHS Digital’s National Health Application and Infrastructure Services (NHAIS) system via Open Exeter from which aggregate LA level reports are produced.

The KC61 and KC65 data come to NHS Digital via the NHSE Screening Quality Assurance Services (SQAS), which collect them from screening laboratories and colposcopy clinics in each region.

The SQAS, which is part of NHSE, is responsible for quality assuring the screening programme including the KC53, KC61 and KC65 returns before final submission.

Data are quality assured by the SQAS on an annual basis. Aggregated data are provided to NHS Digital in a defined format.

Further validation and quality assurance checks are carried out on both the KC and Open Exeter datasets by NHS Digital as part of the publication process.

NHS Digital validates and analyses the KC53, KC61, KC65 data and data from Open Exeter using automated processes developed in SAS³ as well as spreadsheets (Microsoft Excel).

Most of the figures presented in the report and tables are in the form of simple counts and percentages (rounded to 1 or 2 decimal places).

Due to rounding, the sum or percentages in some tables will not always equal 100%.

Definitions and formulae details about how the statistics in the report are calculated are given in Appendix B.

Appendix F gives details of who uses the statistics from publication and what they use them for.

Further validation and quality assurance checks are carried out on both the KC and Open Exeter datasets by NHS Digital as part of the publication process.

NHSE Screening Quality Assurance staff are asked to check some of the tables produced for publication by NHS Digital as part of the validation process.

Users of these statistics should be aware that screening is not 100% accurate and that in any screening programme, there will be some false positive results (samples wrongly reported as having the condition) and some false negative results (samples wrongly reported as not having the condition⁴).

False positives

Some people with a positive screening test result do not actually have the condition being screened for. These people are said to have a ‘false positive’ result.

In cervical screening, false positive results are suggested when an apparent abnormality is detected at screening but no evidence of disease can be found at subsequent investigations.

This may occur if normal cells are mistaken for abnormal cells at initial screening or if minor cell abnormalities were detected at screening that cleared up all on their own.

Given that minor cell abnormalities can clear up on their own, it is not possible to estimate what proportion of cervical screening results are false positives.

False negatives

Some people with a negative screening test result do actually have the condition being screened for. These people are said to have a ‘false negative’ result.

In cervical screening, early cell changes that may lead to cancer may not always be detected.

Abnormal cells on a slide may not be recognised because:

• sometimes they do not look much different from normal cells
• there may be very few abnormal cells on the slide
• the person reading the slide may miss the abnormality (this happens occasionally, no matter how experienced the reader is)

It is also possible that an area of abnormality was present on the cervix but this area was not included in the sample taken and therefore no abnormality could be identified by the laboratory.

There is generally no accepted or expected level of false negatives in the NHS Cervical Screening Programme.

Referral value (RV) is the number of individuals referred to colposcopy (excluding inadequate referrals) per detection of one CIN2 or worse lesion, and is reported in Table 19a of the data tables.

Under the Human Papillomavirus (HPV) primary screening protocol, all individuals are testing for hrHPV as the primary screening test.  Those who have a positive result have cytology prepared.  All individuals who have an hrHPV positive and cytology abnormal result are referred to colposcopy.  Individuals with an hrHPV positive cytology negative result are offered a repeat test in 12 months.  If they continue to have an hrHPV positive result but are cytology negative they are referred for colposcopy after 24 months. Changes are required to the KC61 central data return to enable this to be recorded on parts C1 and C2 but until these changes are made these individuals are not included in the calculation of RV.

Individuals with an HPV positive test along with negative cytology are less likely to have CIN2 or worse than individuals who are HPV positive and have an abnormal cytology result (1.7% of those individuals who have repeat HPV positive/cytology negative results and are then referred to colposcopy compared with 38.5% of individuals referred to colposcopy due to an hrHPV positive/cytology abnormal test).  The impact of the exclusion of this group on RV is therefore considered minimal¹.

Appendix F contains further information and data validation and data quality.

The cervical screening data is made available as soon as possible after they have been compiled and validated (usually the November following the end of the financial year to which the data relate).

A list of cervical screening reports published annually by NHS Digital are available and those published quarterly are available.

‘Age appropriate’ data listed within the publication materials are sourced from the Public Health Outcomes Framework (PHOF) hosted by Open Exeter.

On occasion, this data is updated retrospectively after it has been published. Data is always published correctly at the time of release but is not updated retrospectively to account for these revisions.

As a result, users may notice slight changes to previously published figures.

Most data fields are published in the data tables which are available via the publication webpage.

The data in the tables are also available as CSV files.

Further analysis may be available on request, subject to resource limits and compliance with disclosure control requirements.

An interactive data dashboard is provided as part of the data resources for this publication. The dashboard has been developed in software called Microsoft Power BI and is designed to make data more meaningful by allowing local, regional, and national comparisons over time.

This includes:

• coverage statistics for individuals aged 25 to 64 years (reported by LA and Clinical Commissioning Group (CCG))
• statistics on the time it takes for screening results to be received (reported by LA).
• statistics on the time from screening sample being received by laboratory to authorisation of report (reported by screening region)

The dashboard can be accessed directly.

Time series

For key statistics, the report presents a time series including the current year and previous 10 years. For all other statistics, figures for the current year are compared with the previous year.

The changes in policy described in the main report under ‘Changes to the report’ and in this document’s ‘Impact of NHS reorganisation’ section need to be considered when examining trend data.

Impact of NHS re-organisation

The statistics presented in this publication are presented by upper tier LA rather than Primary Care Organisation (PCO), in line with the responsibilities of LAs for public health. LA data was published in this report for the first time in 2013-14.

LA age-appropriate coverage statistics for previous years are published as part of the Public Health Outcomes Framework (PHOF) here.

When comparing data at the link above with PHOF data published in this report, the differences between regional groupings of LAs should be considered (see ‘Local and regional comparisons’ section).

Data presented by LA are based on the resident population (i.e. individuals who live within the geographical boundary of the LA).

Comparisons with other countries

The main report includes coverage comparisons with other UK countries.

It should be noted that cervical screening programmes in different UK countries cover different age-groups and vary in the frequency of screening and how coverage is calculated.

Data for each country is available via the following links:

Northern Ireland
Scotland

Wales

Local and regional comparisons

Local level statistics are presented at upper tier LA, pathology laboratory and colposcopy clinic.

At a regional level, LA data is aggregated up to 8 reporting regions with sub-regional breakdowns for the South (showing the South East and South West).

LAs are assigned to regions based on region of responsibility within the cervical screening programme during that reporting period. If the responsibility for that LA changes from one reporting period to the next, then the assignment of the LA to a region will also change.

This means that the regional groupings of some LAs for PHOF data in this report will differ from that in the PHOF fingertips tool.

Full details of the LA regional changes are shown below.

Data from pathology laboratories (KC61) are aggregated up to 7 reporting regions with sub-regional breakdowns for North East (showing the North East and Yorkshire and the Humber separately). From 2020-21 onwards, there is no breakdown for Yorkshire and the Humber. From 2019-20 onwards, there is no breakdown for the South East and South West sub-regions.

Data from colposcopy clinics (KC65) are aggregated up to 7 reporting regions with sub-regional breakdowns for North East, Yorkshire and the Humber (showing the North East and Yorkshire and the Humber separately) and the South (showing the South East and South West).

Age and frequency changes to screening policy were introduced in 2003 based on new research evidence (Sasieni et al, 2003) as detailed below.

Target age group changes to 25 to 64

Prior to the target age group change, individuals aged 20 to 64 were included in the screening programme. Beginning in 2004 individuals received their first invitation shortly before their 25th birthday.

Since December 2012, individuals have been invited 6 months before their 25th birthday so that they can decide to be screened by their 25th birthday.

Screening interval changed to be dependent on age

Prior to 2004, national policy was to invite individuals for screening at intervals of not more than 5 years and therefore there was some variation in local practice.

Since 2004 individuals aged 25 to 49 are invited for screening every 3 years whereas those aged 50 to 64 are invited every 5 years.

HPV testing as triage and test of cure (TOC)

A number of sentinel sites began HPV testing as triage for individuals with mild or borderline test results in early 2007.

Improving Outcomes: A Strategy for Cancer (Jan 2011) announced the roll out of HPV testing across England as triage for individuals with borderline or low-grade cervical screening test results and as a test of cure (TOC) for individuals previously treated for cervical abnormalities.

Roll out to all areas began towards the end of March 2012.

Laboratories implemented a phased roll out for the implementation of HPV testing for triage and TOC over a 2 year period to 31 March 2014, and the policy became routine from 1 April 2014.

Prior to the introduction of HPV testing as triage individuals with borderline or low-grade results were recalled for a repeat test in around 6 months and only referred if the abnormality persisted.

HPV testing as triage impact

The introduction of HPV testing as triage has been found to initially increase referrals to colposcopy (Moss et al, 2011)⁶.

At first, the introduction of HPV testing as triage increased the numbers of referrals to colposcopy as referrals can be speeded up where individuals test positive for HPV.

HPV testing as triage also increases the number of individuals who are returned to routine recall status and thereby decreases the numbers of individuals on early repeat recall due to abnormality.

Early repeat recall due to abnormality requires 1 or more further tests, typically around 6 months after the previous test, before the individual can be returned to routine recall.

An evaluation of HPV triage at 6 sentinel sites suggested that it would “…allow approximately a third of all borderline and mildly dyskaryotic individuals to be returned immediately to routine recall…” (Moss et al, 2011, p 8).

HPV primary screening

The NHS Cervical Screening Programme began an HPV primary screening pilot in May 2013 in 6 pathology laboratories (Bristol, Liverpool, London, Manchester, Norwich, and Sheffield).

The pilot aimed to: “establish whether using HPV testing as the primary screen for cervical disease results in better outcomes for women, while minimising over-treatment and anxiety, and whether it is practical to roll out nationally”.⁷

HPV primary screening differs from the usual process for examining cervical samples cytologically, instead the sample is first tested for HPV and where a sample tests positive for HPV a cytology screen is then performed. Therefore cytology acts as the triage.

Evidence suggests that testing for HPV first is more sensitive at detecting abnormalities. HPV primary screening may therefore be a better way of identifying individuals at risk of developing cervical cancer.

In HPV primary screening if the sample is found to be hrHPV negative, the individual is returned to routine recall and invited for screening again in 3 or 5 years’ time depending on her age.

If the sample is hrHPV positive, a slide is prepared from the same sample and is then examined by the cytologist for any abnormal cells.

Individuals who have an hrHPV positive result with a cytology negative result, will be recalled in 12 months for a further screen.  If they remain hrHPV positive and cytology negative at 24 months they will be referred for colposcopy.

A negative hrHPV result will achieve a longer protection than the current cytology method of examining cervical samples.

HPV primary screening was rolled out across England during 2019/20.  Full coverage of the population was achieved by December 2019.

In future individuals who test negative for high risk HPV may not need to attend screening as frequently. The UK National Screening Committee (UK NSC) has evaluated evidence and has recommended that in HPV screening intervals can be extended to 5 years for all age groups.

The implementation of 5 year extended screening intervals is being planned now that HPV primary screening has been fully implemented.

HPV primary screening impact

The implementation of HPV primary screening across England was completed by December 2019 and resulted in a consolidation of cytology service to 8 sites from the previous 48. This impacted on cytology workforce and reduced cytology screening capacity in some areas in the lead up to, and during the implementation.

The change to HPV primary screening and consolidation of services did impact on turnaround times for the cervical screening programme.  In 2021-22, turnaround time improved, with 79.6% of letters received within 2 weeks, an increase of 12.5 percentage points from the previous year.

In January 2013 the NHS Cancer Screening Programmes published the third edition of ‘Achievable standards, Benchmarks for reporting, and Criteria for evaluating cervical cytopathology’ (ABC3).

This outlined a new classification for abnormal cervical cytology, as agreed by the NHSCSP and the British Association for Cytopathology.

Historically, the UK has used the British Society for Clinical Cytology (1986) classification to report cervical cytology.

Elsewhere, other classifications are used, notably the Bethesda Classification (Solomon et al, 2004⁸) which was introduced in the US in 1991.

The new classification adopted by the NHSCSP narrows the gaps between the 2 systems and makes it easier to make international comparisons.

The changes, which were implemented from April 2013, are detailed in the table and section below.
Tables in this publication affected by these changes have been caveated appropriately.

• Prior to April 2013, many samples showing koilocytotic change (which occurs as a result of HPV infection) would have been recorded as borderline change with koilocytosis and recorded as result code ‘8’.
  
  From April 2013 all such cases should have been classified as low grade dyskaryosis (mild dyskaryosis under the old terminology), result code ‘3’.
  
  Although the precise impact of this change is not known, a significant proportion of what used to be classified as borderline change should now be classified as low grade dyskaryosis.
   
• Samples which might previously have been classified as ‘borderline – high-grade dyskaryosis not excluded’, and recorded as result code ‘8’, may have been recorded as high-grade dyskaryosis (moderate), result code ‘7’, or ‘borderline - not otherwise specified’, result code 8, from April 2013.
  
  Again, the impact of this change is not known but is expected to be less than for samples showing koilocytotic change.
   
• The division of ?glandular neoplasia into 2 categories impacted on a number of tables in the report.
  
  ?glandular neoplasia (non-cervical) was previously included in tables showing test results of ?glandular neoplasia. These test results are now given result code ‘0’ and shown in the data tables as negative test results as they are not cervical abnormalities.
  
  The number of test results showing ?glandular neoplasia is relatively small and so the impact of this change on that group is substantial.
  
  The addition of ?glandular neoplasia (non-cervical) to the negative result category has minimal impact as this group makes up the majority of sample test results.
  
  Positive predictive value (PPV) and Referral Value (RV) calculations no longer include ?glandular neoplasia (noncervical) test results/referrals.

Changes to the KC forms are required before the borderline change in squamous cells and endocervical cells can be distinguished in the reported statistics.

Discussions between NHS Digital and NHSE Screening suggest any revisions to reflect terminology and recent programme changes may take some time to implement but work is in progress.

In the meantime these 2 categories are reported together as borderline change.

• Tests showing ?glandular neoplasia (non-cervical) have been recorded on the KC forms as negative from April 2013 onwards as they are non-cervical abnormalities and therefore are dealt with outside of the cervical screening programme.
• ?invasive squamous carcinoma is referred to as ?invasive carcinoma in the tables and commentary for ease of reporting.

The publication is based on information that has been routinely collected by the NHS Cervical Screening Programme for a number of years as part of the operation and performance management of the cervical screening programme.

All data collections used in this publication are now assured by the Data Standards Assurance Service (DSAS) on behalf of the Data Coordination Board (DCB). Previously, this was done by the Burden Advice and Assessment Service (BAAS) procedure (previously known as Review of Central Returns (ROCR)) and licensed by BAAS.

This is to ensure that data collections do not duplicate other collections, minimise the cost to all parties and have a specific use for the data collected.

The standard NHS Digital security and confidentiality policies have been applied in the production of these statistics.

The data are received in aggregate form from the Open Exeter Team (KC53) and SQASs (KC61/KC65) via the secure NHSmail system⁹.

An annual risk assessment is undertaken prior to publication which addresses any potential issues around disclosure.

The following disclosure rules have been applied to this publication:

1. In Table 26b the actual number of biopsies by organisation has been suppressed, leaving totals by region available.
   
   The percentage showing CIN¹⁰ (cervical intra-epithelial neoplasia) or worse has been banded to 2.5% increments.
2. The eligible populations in 2 LAs are relatively small and in these instances their data have been combined and reported under other LAs.
    

Data for the Isles of Scilly is reported under Cornwall and City of London data is reported under Hackney.

Statistics in this report are therefore presented by 150 LAs, 2 of which include another small LA.

1. PHOF outcome figures may show small variances year-on-year as updates are made to historic figures after the data are published.
2. See Public Health Outcomes Framework and Public Health Outcomes Framework 2013 to 2016 for more information
3. Statistical Analysis System (SAS) is an integrated system of software products which enables functions such as data management, statistical analysis, and quality improvement
4. Source: UK National Screening Committee:
5. For more information on HPV triage and test of cure (TOC) see: Cervical screening: programme and colposcopy management
6. Moss, S, Kelly, R, Legood, R, Sadique, Z, Canfell, K, Bin Lew J, Smith, M, Walker, R. 2011, ‘Evaluation of sentinel sites for HPV triage and test of cure: report to the NHS Cancer Screening Programmes’.
7. UK National Screening Committee briefing on the meeting of 25 April 2012. See: http://webarchive.nationalarchives.gov.uk/20150408175925/http://www.screening.nhs.uk/cms.php?folder=3456
8. Solomon D, Nayar R. 2004, ‘The Bethesda System for Reporting Cervical Cytology’, New York, Springer-Verlag’
9. See https://digital.nhs.uk/nhsmail/secure-email-standard for more information.
10. See Appendix E on Outcomes of Gynaecological Referrals for further information about cervical intra-epithelial neoplasia (CIN).