What is cervical screening?

Cervical screening is not a test for cancer. It is a method of preventing cancer by detecting and treating early abnormalities which, if left untreated, could lead to cancer in a woman's cervix (the neck of the womb). The first stage in cervical screening is taking a sample using Liquid based Cytology (LBC).

A sample of cells is taken from the cervix for analysis. A doctor or nurse inserts an instrument (a speculum) to open the woman's vagina and uses a spatula to sweep around the cervix. Most women consider the procedure to be only mildly uncomfortable.

Early detection and treatment can prevent 75 per cent of cancers developing but like other screening tests, it is not perfect. It may not always detect early cell changes that could lead to cancer.

What is LBC?

Liquid based cytology (LBC) is a new way of preparing cervical samples for examination in the laboratory. The sample is collected in a similar way to the conventional smear, using a special device which brushes cells from the neck of the womb. Rather than smearing the sample onto a microscope slide as happens with the conventional smear, the head of the brush, where the cells are lodged, is broken off into a small glass vial containing preservative fluid, or rinsed directly into the preservative fluid. The sample is sent to the laboratory where it is spun and treated to remove obscuring material, for example mucus or pus, and a random sample of the remaining cells is taken. A thin layer of the cells is deposited onto a slide. The slide is examined in the usual way under a microscope by a cytologist.

Possible future developments

Computer assisted detection of cervical abnormalities is a possibility for the future.

The HPV vaccination programme started in September 2008 with all 12- to 13-year-old and 17- to 18-year-old girls being offered the vaccine. A catch-up programme was also announced at this time with 13- to 18-year-old girls being offered the vaccine over the following two academic years.

An accelerated catch-up programme was announced in December 2008 so that all girls born on or after 1 September 1990 could be protected before the end of the academic year 2009/10.

For more information about the vaccine see www.immunisation.nhs.uk/Vaccines/HPV/.

It will be many years before the vaccination programme has an effect upon cervical cancer incidence so the programme is not planning any changes yet. Vaccinated women are advised to continue accepting their invitations for cervical screening as the vaccination will not prevent all types of cervical cancer.

What does the NHS Cervical Screening Programme do?

The programme aims to reduce the number of women who develop invasive cervical cancer (incidence) and the number of women who die from it (mortality). It does this by regularly screening all women at risk so that conditions which might otherwise develop into invasive cancer can be identified and treated.

Who is eligible for cervical screening?

All women between the ages of 25 and 64 are eligible for a free cervical screening test every three to five years. In the light of evidence published in 20031 the NHS Cervical Screening Programme now offers screening at different intervals depending on age. This means that women are provided with a more targeted and effective screening programme.

The new intervals are:

Age group (years)	Frequency of screening
25	First invitation
25 - 49	3 yearly
50 - 64	5 yearly
65+	Only screen those who have not been screened since age 50 or have had recent abnormal tests

The NHS call and recall system invites women who are registered with a GP. It also keeps track of any follow-up investigation, and, if all is well, recalls the woman for screening in three or five years time. It is therefore important that all women ensure their GP has their correct name and address details and inform them if these change.

Women who have not had a recent test may be offered one when they attend their GP or family planning clinic on another matter. Women should receive their first invitation for routine screening at 25.

Why are women under 25 not invited?

This is because changes in the young cervix are normal. If they were thought to be abnormal this could lead to unnecessary treatment which could have consequences for women's childbearing.2 Any abnormal changes can be easily picked up and treated from the age of 25. Rarely, younger women experience symptoms such as unexpected bleeding or bleeding after intercourse. In this case they should see their GP for advice.

In June 2009 the Advisory Committee on Cervical Screening  reviewed the policy of starting screening at age 25 and agreed unanimously there should be no change in the current policy.

A research paper, Sasieni P, Castañón A, Cuzick J. Effectiveness of cervical screening with age: population based case-control study of prospectively recorded data. BMJ 2009; 339:b2968, focusing on women screened under the age of 25 was published in the BMJ. It stated:

'Cervical screening in women aged 20-24 is substantially less effective in preventing cancer (and in preventing advanced stage tumours) than is screening in older women'

Why are women over 65 not invited?

Women aged 65 and over who have had three consecutive negative results are taken out of the call recall system. The natural history and progression of cervical cancer means it is highly unlikely that such women will go on to develop the disease. Women aged 65 and over who have never had a test are entitled to one.

What about women who are not sexually active?

The NHS Cervical Screening Programme invites all women between the ages of 25 and 64 for cervical screening. But if a woman has never been sexually active, then the research evidence shows that her chance of developing cervical cancer is very low indeed. We do not say no risk, only very low risk. In these circumstances, a woman might choose to decline the invitation for cervical screening on this occasion. If a woman is not currently sexually active but has been in the past, then we would recommend that she continues screening.

When was the NHS Cervical Screening Programme set up?

Cervical screening began in Britain in the mid-1960s. By the mid-1980s, although many women were having regular smear tests, there was concern that those at greatest risk were not being tested, and that those who had positive results were not being followed up and treated effectively.

The NHS Cervical Screening Programme was set up in 1988 when the Department of Health instructed all health authorities to introduce computerised call-recall systems and to meet certain quality standards.

How many women are screened?

The programme screens almost four million women in England each year. Of the women in the target age group most were tested following an invitation and the rest were screened opportunistically at the suggestion of the sample taker or of the woman herself. For clinical reasons some women have more than one test during the course of a year and nearly four and a half million samples are examined by pathology laboratories every year.

Click here for the latest statistics on the NHS Cervical Screening Programme.

How is the programme organised?

More than 100,000 people are involved in cervical screening. They include the doctors and nurses who take the samples in GP surgeries and community clinics, the laboratory staff who review them and the people who run the computer systems.

Who does what in the NHS Cervical Screening Programme?

The national office of the NHS Cancer Screening Programmes, based in Sheffield, is responsible for improving the overall performance of the programme. Set up in 1994, its priorities are to:

• develop systems and guidelines which will assure a high quality of cervical screening throughout the country
• identify important policy issues and help resolve them, and improve communications within the programme and to women

Every Primary Care Trust (PCT) has a nominated person responsible for its cervical screening programme and implementing the national guidelines.

Regional directors of public health are responsible for the quality assurance network in their region.

How much does the programme cost and how is it funded?

Cervical screening - including the cost of treating cervical abnormalities - has been estimated to cost around £157 million a year in England.

Primary Care Trusts commission cervical screening from the overall allocation they receive from the Department of Health.

Is cervical screening effective?

Whilst cervical screening cannot be 100 per cent effective, cervical screening programmes have been shown to reduce the incidence of cancer in a population of women. For example:

Percentage of Cancer Preventable

(Protection offered by a single negative smear)

	20-39 years	40-54 years	55-69 years
3-yearly screening	41%	69%	73%
5-yearly screening	30%	63%	73%
Sasieni, Adams, and Cuzick, BJC 2003

Coverage of the target population

The effectiveness of the programme can also be judged by coverage. This is the percentage of women in the target age group (25 to 64) who have been screened in the last five years. If overall coverage of 80 per cent can be achieved, the evidence suggests that a reduction in death rates of around 95 per cent is possible in the long term. In 2008/9 the coverage of eligible women was 78.9 per cent3

Oral contraceptives and cervical cancer

Further evidence suggests that long-term use of combined oral contraceptives or progestogen-only injectable contraceptives is associated with a small increased risk of cervical cancer. The level of risk returns to that for never-users within 10 years of stopping use

What is breast screening?

Breast screening is a method of detecting breast cancer at a very early stage. The first step involves an x-ray of each breast - a mammogram - which is taken while carefully compressing the breast. Most women find it a bit uncomfortable and a few find it painful. The mammogram can detect small changes in breast tissue which may indicate cancers which are too small to be felt either by the woman herself or by a doctor.

What does the NHS Breast Screening Programme do?

The NHS Breast Screening Programme provides free breast screening every three years for all women in the UK aged 50 and over. Around one-and-a-half million women are screened in the UK each year. The NHS Breast Screening Programme is phasing in an extension of the age range of women eligible for breast screening to those aged 47 to 73 starting in 2010.

The NHS Breast Screening Programme will extend the age range of women eligible for breast screening to ages 47 to 73 by 2012.

Because the programme is a rolling one which invites women from GP practices in turn, not every woman will receive an invitation as soon as she is 50. But she will receive her first invitation before her 53rd birthday.Once women reach the upper age limit for routine invitations for breast screening, they are encouraged to make their own appointment.

The NHS Breast Screening Programme is an effective part of the UK's efforts to reduce the death toll from breast cancer. In September 2000, research was published which demonstrated that the screening programme had lowered mortality rates from breast cancer in the 55-69 age group1.

In 2010, research undertaken by Stephen Duffy and others demonstrated that  the benefit of mammographic screening in terms of lives saved is greater than the harm in terms of overdiagnosis. Between 2 and 2.5 lives are saved for every overdiagnosed case.

When was the NHS Breast Screening Programme set up?

The programme was set up by the Department of Health in 1988 in response to the recommendations of a working group, chaired by Professor Sir Patrick Forrest, which had been set up to consider whether or not to implement a population screening programme in the UK. The report Breast Cancer Screening was published in 1986, and became known as The Forrest Report. The NHS Breast Screening Programme was the first of its kind in the world. It began inviting women for screening in 1988 and national coverage was achieved by mid 1990s.

Click here for the latest statistics on the NHS Breast Screening Programme (England)
(A separate browser window will open).

How is the programme organised?

There are 82 breast screening units across the UK, each inviting a defined population of eligible women (aged 50 to 70) through their GP practices. Women are invited to a specialised screening unit, which can be hospital based, mobile, or permanently based in another convenient location such as a shopping centre.

The NHS Breast Screening Programme is nationally coordinated. It sets national standards which are monitored through a national quality assurance network. For England, there is a national coordination office, based in Sheffield, and an advisory committee which oversees the programme and reports to government ministers.

The programme was commended as a "model service" in the Health Select Committee's third report into breast cancer services in July 1995.

How much does the programme cost?

In England, the budget for the breast screening programme is now estimated to be approximately £75 million. This works out at about £37.50 per woman invited or £45.50 per woman screened.

How will the programme develop in the future?

In December 2007, the Department of Health's Cancer Reform Strategy announced that from 2012 the NHS Breast Screening Programme would be extended to cover women between the ages of 47 and 73. This means that all women will get two extra screening invitations in their lifetime. It also means that all women will get their first screening invitation by their 50th birthday.

The age extension will be phased in across England over a three-year period, with full coverage from 2012. Before that begins, however, a pilot study is being undertaken in six areas across England that have volunteered to take part. The pilot study will provide information which can be used in the planning and rollout of the age extension across the rest of England.

Women aged 50-70 in the pilot areas are invited for screening as usual. In order for the pilot to be evaluated, the female population that falls within the extended screening ages has been randomised. Around half of the women aged 47-49 and 71-73 in the pilot areas have been selected at random to receive screening invitations. This means that the pilot only affects some women aged 47-49 and 71-73, as all women aged 50-70 continue to get their screening invitations as normal.

For more information see;
http://clinicaltrials.gov/ct2/show/NCT00890864?term=NCT00890864&rank=1.

A study looking at targeting the younger cohort and comparing it with the status quo has been undertaken. An extension of the modelling to the older cohort is included in the appendix.

ScHARR Initital Assessment Report (PDF 183Kb).

Digital mammography

The introduction of digital mammography was started in 2005. Whereas conventional mammography captures images of breast tissue on x-ray film, digital mammography uses computer imaging. Any new equipment is evaluated for both technical effectiveness and user acceptability. See evaluation and clinical assessment of equipment for further information. There was also a study of the acceptability to women of digital screening. This has looked at their perceived pain or discomfort and levels of satisfaction with the experience when compared with conventional mammography.

By 2010 every breast screening unit should have at least one digital set for assessment.

Why are women under 50 not routinely invited?

Women under 50 are not currently offered routine screening. This is because film mammograms are not as effective in pre-menopausal women. as the density of the breast tissue makes it more difficult to detect problems, and also because the incidence of breast cancer is lower in this age group. The average age of the menopause in the UK is 50. As women go past the menopause, the glandular tissue in their breast "involutes" and the breast tissue is increasingly made up of only fat. This is clearer on the film mammogram and makes interpretation of the x-ray more reliable.

The extension of the NHS Breast Screening programme to women aged 47 will be complete by 2012. The DMIST study has shown that digital mammography is better for screening younger women and women with denser breasts, and is equally effective as film mammography in older women.

Women can ask their GP to refer them to a hospital breast clinic if they are concerned about a specific breast problem or otherwise worried about the risk of breast cancer. This is not part of the NHS Breast Screening Programme, which uses a routine call and recall system to invite well women. However, the same techniques are used in both breast screening clinics and hospital breast clinics for diagnosing breast cancer and many staff work in both settings.

Does breast screening save lives?

The programme in the UK has screened more than 19 million women and has detected around 117,000 cancers.

A report by the Department of Health Advisory Committee published in 1991 suggested that the programme would save 1,250 lives each year by 2010.2

The World Health Organisation's International Agency for Research on Cancer (IARC) concluded that mammography screening for breast cancer reduces mortality. The IARC working group, comprising 24 experts from 11 countries, evaluated all the available evidence on breast screening and determined that there is a 35 per cent reduction in mortality from breast cancer among screened women aged 50 - 69 years old. This means that out of every 500 women screened, one life will be saved.3

In 2010, research undertaken by Stephen Duffy and others demonstrated that the benefit of mammographic screening in terms of lives saved is greater than the harm in terms of overdiagnosis. Between 2 and 2.5 lives are saved for every overdiagnosed case.

Why screen for bowel cancer?

About one in 20 people in the UK will develop bowel cancer during their lifetime. It is the third most common cancer in the UK, and the second leading cause of cancer deaths, with over 16,000 people dying from it each year.1

Regular bowel cancer screening has been shown to reduce the risk of dying from bowel cancer by 16 per cent2.

What is the purpose of bowel cancer screening?

Bowel cancer screening aims to detect bowel cancer at an early stage (in people with no symptoms), when treatment is more likely to be effective.

Bowel cancer screening can also detect polyps. These are not cancers, but may develop into cancers over time. They can easily be removed, reducing the risk of bowel cancer developing.

How is the NHS Bowel Cancer Screening Programme organised?

The NHS Bowel Cancer Screening Programme is now being rolled out nationally and will achieve nation wide coverage by 2009.

Programme hubs operate a national call and recall system to send out faecal occult blood (FOB) test kits, analyse samples and despatch results. Each hub is responsible for coordinating the programme in their area and works with up to 20 local screening centres.

The screening centres provide endoscopy services and specialist screening nurse clinics for people receiving an abnormal result. Screening centres are also responsible for referring those requiring treatment to their local hospital multidisciplinary team (MDT).

Who is eligible for bowel cancer screening?

The NHS Bowel Cancer Screening Programme offers screening every two years to all men and women aged 60 to 69. People over 70 can request a screening kit by calling a freephone helpline when the programme reaches their area.

Will GPs be involved?

GPs are not directly involved in the delivery of the NHS Bowel Cancer Screening Programme but they will be notified when invitations for bowel cancer screening are being sent out in their area. They will also receive a copy of the results letters sent to their patients.

How much does bowel screening cost?

The cost of the NHS Bowel Cancer Screening programme is £76.2 million.

How will the screening process work?

Men and women eligible for screening will receive an invitation letter explaining the programme and an information leaflet entitled Bowel Cancer Screening - The Facts. About a week later, an FOB test kit will be sent out along with step-by-step instructions for completing the test at home and sending the samples to the hub laboratory. The test will then be processed and the results sent within two weeks.

What happens next?

Around 98 in 100 people will receive a normal result and will be returned to routine screening. They will be invited for bowel cancer screening every two years if still within the eligible age range.

Around 2 in 100 people will receive an abnormal result. They will be referred for further investigation and usually offered a colonoscopy.

Around 4 in 100 people may initially receive an unclear result which means that there was a slight suggestion of blood in the test sample. This could be caused by conditions other than cancer such as haemorrhoids (piles). An unclear result does not mean that cancer is present, but that the FOB test will need to be repeated. Most people who repeat the test will then go on to receive a normal result.

How does the FOB test work?

Polyps and bowel cancers sometimes bleed, and the faecal occult blood (FOB) test works by detecting tiny amounts of blood which cannot normally be seen in bowel motions. 'Occult' means hidden. The FOB test does not diagnose bowel cancer, but the results will indicate whether further investigation (usually a colonoscopy) is needed.

People who receive an abnormal result will be offered an appointment with a specialist nurse. The nurse will explain what a colonoscopy involves, assess the patient's fitness for the procedure, and answer any questions.

What is a colonoscopy?

A colonoscopy is an investigation that involves looking directly at the lining of the large bowel. A sedative is given and then a thin, flexible tube with a tiny camera attached (a colonoscope) is passed into the back passage and guided around the bowel. If polyps are found, most can be removed painlessly, using a wire loop passed down the colonoscope tube. These tissue samples are then checked for any abnormal cells that might be cancerous.

What are the risks of colonoscopy?

A colonoscopy is the most effective way to diagnose bowel cancer and for most people it is a straightforward procedure. However, as with most medical procedures, there is the possibility of complications. These can include heavy bleeding (about a one in 150 chance) which will need further investigation or medical advice. There is approximately a one in 1,500 chance that the colonoscope could cause a hole (perforation) in the wall of the bowel. In extremely rare cases , colonoscopy may result in death. Current evidence suggests that this may only happen in around one in 10,000 cases.

There is no organised screening programme for prostate cancer but an informed choice programme, Prostate Cancer Risk Management, has been introduced.

If you are worried about a specific problem, or otherwise worried about the risks of cancer, then you should talk to your GP. Information packs have been sent to General Practitioners to assist them in the counselling of men who enquire about testing. The pack will help the primary care team to provide men with information on the benefits and limitations of the PSA test. It comprises a reference booklet and summary sheet for the primary care team and a book of tear off patient information sheets. Prostate CancerStats are also included.

Why isn't there a national screening programme for prostate cancer?

All screening programmes cause some harm. This could include false alarms, inducing anxiety, and the treatment of early disease which would not otherwise have become a problem.

When considering population screening programmes the benefits and harms must be carefully assessed, and the benefits should always outweigh the harms.

Until there is clear evidence to show that a national screening programme will bring more benefit than harm, the NHS will not be inviting men who have no symptoms for prostate cancer screening.

In 1968, Wilson and Jungner of the World Health Organisation developed ten principles which should govern a national screening programme. These are:

To date, prostate cancer screening fulfils only the first condition. See the Health Technology Assessment Programme's monograph Diagnosis, management and screening of early localised prostate cancer: a review for details.

New evidence from a prostate cancer screening trial in Europe has shown that screening reduced mortality by 20 per cent. However, this was associated with a high level of over treatment. To save one life, 48 additional cases of prostate cancer needed to be treated.

The UK National Screening Committee has recommended that a prostate cancer screening programme should not be introduced in England at this time, but they will continue to keep the situation under review.

Although evidence does not yet support population screening for prostate cancer. there is considerable demand for the PSA test amongst men worried about the disease. In response to this the Government has introduced a PSA Informed Choice Programme.

The key elements are the provision of high quality information for men requesting the test. This should enable men to decide whether or not to have the test based on the available evidence about risks and benefits. After consideration of the information men choosing to have the test may do so free on the NHS.  Improvements to the PSA test have also been made. The office of the NHS Cancer Screening Programmes manages this work.