This section gives information to help you understand how cervical screening is done, and what happens if you have an 'abnormal' test result. We hope that it answers some of the questions you may have about cervical screening, and the treatment you may need if you have an abnormal test result.

Cancerbackup has further information on cervical cancer, which is for women who have been diagnosed as having cancer of the cervix.

Detailed information about the UK cervical screening programme is in our health professional section.

The cervix and cervical screening

The cervix is the lower part of the uterus, or womb. Sometimes it is also called the neck of the womb.

The position of the cervix in relation to the other female reproductive organs

It is possible for your doctor or nurse to see and feel the cervix during an internal (vaginal) examination.

The surface layer of the cervix is made up of two different types of cells: flat cells called squamous cells and longer cells called columnar cells. The place where these cells meet is known as the transformation zone. Cells in this area can become abnormal. It is these cells, on the surface of the cervix, that are examined in a cervical screening test.

The transformation zone area of the cervix

The cells lining the cervical canal (endocervix) produce mucus – they are known as glandular cells. Changes to these cells can sometimes be detected by cervical screening.

Cervical screening

Cervical screening is a way of preventing cancer. The first stage in cervical screening is taking a sample of cells from the cervix. The sample can be taken using either a cervical smear or a method known as liquid-based cytology.

Under the present UK Department of Health guidelines:

Women are sent their first invitation for routine cervical screening at the age of 25.
They are then invited for screening every three years until the age of 49.
From the age of 50 to 64 they are invited for screening every five years.
At the age of 65, women are no longer invited to have cervical screening unless they have had recent cervical changes. Women aged 65 and over who have never had a screening test are entitled to have one.

Women who have had treatment for abnormal cells on the cervix may need to have a screening test more often. Your doctor can discuss this with you.

Where to go for your screening test

You will be sent a letter from your local primary care trust or GP asking you to make an appointment for your screening test. Most women choose to have the test done by their GP or practice nurse. You can ask to have it done by a female doctor or nurse if you prefer.

Cervical screening tests can also be done at community clinics, such as family planning, Well Woman, sexual health or genitourinary clinics. NHS Direct (phone 0845 4647) can give you details of your local clinics.

You cannot be tested during your period so make sure that you get an appointment before or after your period is due. It is best to have the test in the middle of your menstrual cycle, when you are midway between periods.

Can cervical screening prevent cancer?

Yes – for most women. Regular cervical screening every 3–5 years is the best way to detect changes to the cells of the cervix. Early detection and treatment can prevent cancer from developing in around 75% of cases. Almost half of the women who develop cervical cancer in the UK have never had a cervical screening test.

Benefits and difficulties of cervical screening

To help you make a decision about whether or not to go for screening, the main benefits and difficulties of cervical screening are explained below:

Benefits

Cervical screening reduces the risk of developing cervical cancer.
Because of cervical screening, cervical cancer is now an uncommon illness in the UK.
The number of women who develop cervical cancer has halved since the 1980s due to most women regularly having cervical screening.
NHS cervical screening saves over 1,000 lives a year.

Difficulties

Cervical screening can show minor changes that may go back to normal on their own, but knowing they are there can make you worry.
Sometimes, too few cells are taken or the cells cannot be seen properly and the test will need to be done again.
Regular cervical screening can prevent about 7 or 8 of every 10 cervical cancers but it does not prevent every case.
Cervical screening does not pick up every abnormality of the cervix.
Some women find having the test an unpleasant experience.

Reliability of cervical screening

Cervical screening can prevent around 75% of cancers, but like other screening tests it is not perfect. It may not always detect early cell changes that may lead to cancer. Abnormal cervical cells on your slide may not be recognised because:

Sometimes they do not look very different from normal cells.
There may be very few abnormal cells on the slide.
The person looking at and assessing the slide may miss the abnormality. This happens occasionally, no matter how experienced the person is.

Occasionally a test will have to be taken again because:

The cervical cells on your slide may have been hidden by blood or mucus.
There may not have been enough cervical cells on your sample to give an accurate assessment.
Your sample may not have been properly prepared.
Your slide or container may have been broken.
You may have an infection that needs to be treated before a clear sample can be taken.

As screening is not 100% effective in detecting changes to the cervix, you should see your GP if you have any unusual symptoms, such as bleeding after sex or between periods.

What happens to test samples once they have been looked at?

The laboratory that looks at your sample will keep it for at least 10 years. Your latest result can then be compared with the ones you have had before. This is to make sure you get the treatment you may need. All screening records, including your samples, can be reviewed. If a review is needed, the staff working in the screening service will need to look at your screening records.

On the rare occasion that a review shows that you should have been cared for differently, you will be contacted. For more details about NHS record keeping you can contact NHS Direct on 0845 4647.

Cervical screening tests

Cervical screening may be done either using a smear test, or a test known as liquid-based cytology (LBC). Both these tests are described below. The tests are not for diagnosing cancer. They are to check the health of the cervix and to detect early changes in the cells of the cervix, which may develop into cancer in the future.

The screening test is a very simple procedure and takes less than five minutes. It can be uncomfortable but should not be painful. The person carrying out the test should explain the procedure and you should feel able to ask questions at any time.

The smear test

Once you are lying comfortably on the couch the doctor or nurse will gently insert an instrument called a speculum into the vagina to keep the vagina open. A small disposable spatula is then used to take a sample of cells from the cervix. Sometimes a small brush is used to collect the cells. The cells are spread on to a glass slide and sent to a laboratory to be examined under a microscope.

Liquid-based cytology

Liquid-based cytology (LBC) is another way of collecting cells from the cervix. The sample is taken in a similar way to a smear, but uses a special brush that gently takes cells from the cervix. The head of the brush is then rinsed into a small container of preservative or the head of the brush may be snapped off and put into the container. The container is then sent to the laboratory to be checked.

In the laboratory the cells are put onto a glass slide. Liquid-based cytology preserves more cells and makes the need for a second test less likely than the smear test.

Results

You will be sent the results of the cervical screening test by letter within six weeks of having the test. A copy of the report is also sent to the GP practice where the test was done. If you do not hear anything after that time, you can phone the surgery or clinic and ask them to check up on your results.

If the results show that there are abnormal cells in the cervix, you will be contacted and another test will be arranged. Alternatively, an appointment may be arranged with a doctor who specialises in women's health (gynaecologist) or a nurse colposcopist.

Abnormal cervical screening test results

A cervical smear or liquid-based cytology test is the routine test for detecting early changes in the cells of the cervix. Most women have a normal result. The test will find that some women have changes in the cells of the cervix. This is known as an abnormal result, which means that the laboratory has found some cell changes that may need further investigation. Often the changes may be due to inflammation or infection. Sometimes certain medicines such as hormonal therapies (for gynaecological conditions or breast cancer) can cause changes in the cervix. For this reason, it is important to let the person carrying out the screening know about any medicines that you are taking.

Cervical intra-epithelial neoplasia

Sometimes the abnormality may be due to changes in the squamous cells of the cervix. This is known as CIN, which stands for cervical intra-epithelial neoplasia. The screening report may refer to the changes as dyskaryosis.

These abnormal cells are not cancerous, but if left untreated they can sometimes go on to develop into cancer of the cervix.

As the cells can sometimes develop into cancer they are also sometimes called pre-cancerous changes.

Cervical glandular intra-epithelial neoplasia

Occasionally a screening test may find changes in the glandular cells which line the cervical canal. Changes to these cells seem to go through the same stages as CIN, but are called cGIN, which stands for cervical glandular intra-epithelial neoplasia. If left untreated these changes may develop into a type of cancer known as adenocarcinoma. It is much less common for changes to occur in these cells.

A cervical screening test can also detect early cancer of the cervix, but most women with an abnormal test result have early cell changes and not cancer.

It is important to remember that very few women with an abnormal test result actually have cancer of the cervix.

Grades of CIN

CIN (cervical intra-epithelial neoplasia) is divided into grades, which describe how deeply the abnormal cells have gone into the surface layer of the cervix.

CIN 1 Only one-third of the thickness of the surface layer of the cervix is affected.

CIN 2 Two-thirds of the thickness of the surface layer of the cervix is affected.

CIN 3 The full thickness of the surface layer of the cervix is affected.

With all three grades of CIN, often only a small part of the cervix is affected by abnormal changes.

CIN 3 is also known as carcinoma-in-situ. Although this sounds like cancer, CIN 3 is not cancer of the cervix. It is only if the deeper layers of the cervix have been affected by the abnormal cells that a cancer has developed. However, it is important that it is treated as soon as possible.

A screening test can show that CIN is present, but it cannot always show how deeply the abnormal cells go into the cervix. In order to find the grade of the CIN, further tests may need to be carried out. During the further tests, samples (biopsies) of the abnormal areas of the cervix may be taken. The biopsies are looked at under a microscope to find the grade of the CIN. This makes it easier for the doctor to decide on the most appropriate type of treatment for you.

We have a section on cancer of the cervix which may help if it is appropriate.

Causes of CIN

The exact cause of CIN (cervical intra-epithelial neoplasia) is still unknown. However, the main cause is infection of the cervix with certain types of human papilloma virus (HPV).

HPV (often known as the wart virus) is a very common infection. There are over 100 types of the virus and the commonest types can cause warts on the hands or verrucas on the feet. Some types can affect the genital area including the cervix, although not all of these types will show any symptoms (such as warts). The types of HPV that cause genital warts are not the same as the types that can lead to CIN. The types that cause genital warts are known as low-risk types.

Genital HPV is spread by direct skin-to-skin contact during sex with someone who has the infection. As this virus is sexually transmitted, the possibility of contact with it increases with the number of partners a woman or her partner has had, and it is more common in women who become sexually active at a young age.

HPV is so common that most sexually active women will be exposed to it at some time in their life. There is evidence that barrier methods of contraception, such as the cap or condoms, give some protection against the spread of HPV, but they will not cover all the susceptible areas.

In most women, their body’s own immune system will get rid of the HPV naturally without them ever knowing it was there.

Some types of HPV can make women more likely to develop CIN. They are known as high-risk types of HPV. In some women the high-risk HPV causes changes in the cervix that show up as an abnormality during the screening tests. Extremely rarely, these changes can go on to develop into CIN or cervical cancer if they are left untreated. Through regular cervical screening, the changes caused by HPV can be picked up early and any treatment needed is easy and effective.

Women who smoke are about twice as likely to develop CIN as non-smokers.

There is also some research to suggest that women who take the contraceptive pill for longer than 10 years are slightly more likely to develop cervical cancer. If you are concerned about taking the pill, please discuss it with your GP or family planning clinic.

Symptoms of CIN

CIN (cervical intra-epithelial neoplasia) has no symptoms, so it is essential for women to have regular cervical screening tests to detect any early cell changes.

Tests after an abnormal cervical screening result

If the result of your cervical screening test shows that there are changes in the cells of the cervix, you should have the chance to discuss this with your GP or practice nurse. You can also discuss it with the nurses at Cancerbackup.

Mild changes

Most abnormal results from screening tests show only very minor changes. These are called borderline or mild changes (or mild dyskaryosis). Many of these will go back to normal on their own, so your GP may simply arrange for you to have further screening tests 6, 12 and 24 months later. If you smoke, it may help if you try to give up, as this will make it more likely that your cervical cells go back to normal.

If your second screening test still shows abnormal cells, your GP or practice nurse may arrange for you to have some further tests. On the other hand, some doctors will refer you for treatment for any abnormality, however minor.

CIN 2 or 3

A smaller number of women will have moderate or severe changes (CIN 2 or CIN 3). These are known as moderate or severe dyskaryosis. If this is the case, your GP or practice nurse will suggest that you have a further test, known as colposcopy, within a few weeks.

If you need to have colposcopy you will be referred to your local cervical screening department, which is usually at a hospital outpatients clinic. You do not usually have to stay overnight. Almost all hospitals with gynaecological units have the facilities to do colposcopy.

Colposcopy

Colposcopy shows the cervix in detail using a colposcope. A colposcope is a specially adapted type of microscope. Colposcopy may be carried out by a specialist doctor or a nurse colposcopist. Doctors and colposcopy nurses follow national guidelines when deciding on whether further tests or treatment are needed.

The colposcope acts like a magnifying glass so that the doctor or nurse can see the whole cervix in more detail. Before your test you will have a chance to discuss your screening test results, and any worries that you may have, with the doctors or nurses at the clinic.

A nurse will help you to position yourself on the couch. When you are lying comfortably the doctor or nurse colposcopist will use a speculum, in the same way as in the screening test, to hold the vagina open. The cervix is then painted with a liquid to make the abnormal areas show up more clearly. A light is shone on to the cervix and the doctor will look through the colposcope (which stays outside your body) to examine the surface of the cervix. A small sample of the cervix (a biopsy) may be taken to be looked at under a microscope.

Colposcopy takes a bit longer than the screening test – about 15–20 minutes. Usually it is not painful, but it may be uncomfortable. If the abnormal area still cannot be seen clearly with a colposcope, the doctor or nurse colposcopist may arrange for you to have a cone biopsy.

Cone biopsy

The doctor takes a small cone-shaped section of the abnormal tissue from the cervix for examination under a microscope. This is normally done under local anaesthetic, although sometimes a general anaesthetic may be used. Looking at the tissue that has been removed can show whether the abnormal cells are CIN 1, 2 or 3 or whether deeper levels of the cervix are affected.

Cone biopsy

Afterwards, a small pack of gauze (like a tampon) may be put into the vagina to prevent bleeding. This is usually removed within 24 hours.

It is normal to have some light bleeding and discharge for a few days after your operation. Sex and strenuous exercise should be avoided for at least 2–4 weeks to allow the cervix to heal properly.

Occasionally a cone biopsy can make the cervix slightly weaker, which may increase the risk of miscarriage during pregnancy. In this situation, miscarriage can often be prevented by putting a stitch into the cervix during pregnancy to strengthen it. Your doctor can discuss this with you in more detail if you are concerned about possible future pregnancies. A cone biopsy will not affect your ability to enjoy sex.

Extremely rarely, after a cone biopsy the cervix can become very tightly closed. This can make it harder for sperm to enter the uterus and so can affect the chances of becoming pregnant naturally. If you are still having periods after your cone biopsy, you can be reassured that the cervix is not completely closed.

Treating CIN

The treatment for CIN (cervical intra-epithelial neoplasia) partly depends on whether it is grade 1, 2 or 3. Often, cells showing CIN 1 will return to normal without any treatment at all. If your doctor or nurse colposcopist decides not to treat these minor changes, further screening tests should be done at 6, 12 and 24 months to make sure that further cell changes do not take place. Some doctors prefer to treat any abnormality, however minor. All doctors and researchers agree that CIN 2 and 3 should be treated.

Main treatments

The main treatments for CIN either remove the abnormal area or destroy the abnormal cells.

Ways of removing the abnormal area include:

large loop excision of the transformation zone (LLETZ)
a cone biopsy
(very rarely) a hysterectomy.

Ways of destroying the abnormal area (so that normal cells can grow back in their place) include:

laser therapy
cold coagulation
cryotherapy

Nowadays, the LLETZ is the most common treatment method used.

How treatments are given

Most women need only one of the treatments described on these pages. All of the treatments are usually very successful in removing the abnormal cells. The type of treatment you have will depend on a number of factors. These will include the facilities available at your local hospital and the type of treatment that your doctor feels would be best for you.

LLETZ, laser therapy, cryotherapy, cold coagulation (and sometimes cone biopsies) are normally carried out in a hospital outpatient clinic, using a local anaesthetic. Most women need only one session of treatment.

Before your treatment the nurse will help you to lie comfortably on the couch. The doctor will then use a speculum to hold the vagina open, in the same way as a smear or LBC test.

Try to relax as much as possible and don’t be afraid to ask the doctor or nurse as many questions as you like about your treatment. The treatment itself is likely to take about 5–10 minutes and, although it may be uncomfortable, it is not painful.

The different types of treatment

Large loop excision of the transformation zone
This can usually be done under a local anaesthetic. Once you are lying comfortably on the couch, the doctor will put some local anaesthetic on to the cervix to numb it. A thin wire is used to cut through and remove the affected area.

Cone biopsy
This is a way to diagnose CIN if the abnormal area cannot be seen clearly with a colposcope. It can also be used as a treatment for CIN. A small, cone-shaped piece of cervix, containing the abnormal cells, is removed. Nowadays, this is usually done under local anaesthetic, using a laser as a 'knife'.

Laser therapy
Under local anaesthetic, a laser beam is pointed on to the abnormal areas of the cervix and the cells are destroyed. During the treatment you may notice a slight burning smell from the laser. This is quite normal.

Cold coagulation
This is a misleading name, as the abnormal cells are removed by heating, not freezing. After a local anaesthetic, a hot probe is placed on the surface of the cervix. You will not feel the heat of the probe.

Cryotherapy
Under a local anaesthetic, a probe is put on the cervix to freeze the abnormal cells. Cryotherapy has a slightly lower success rate than the other treatments for CIN and so it is less commonly used now.

Hysterectomy
In women who are past childbearing age or who do not want to have more children, an operation to remove the womb (hysterectomy) is sometimes done for persistent or severe CIN, where women have other gynaecological problems as well. For women who have not not yet had the menopause, the ovaries will not be removed with the womb, so this treatment will not bring on an early menopause. If you are going to have a hysterectomy you can contact Cancerbackup for more information.

After treatment

Unless you have had a hysterectomy or possibly a cone biopsy, you will be able to go home from hospital on the day that you are treated.

Although most women feel fine after LLETZ, cone biopsy, laser therapy, cryotherapy or cold coagulation, some women feel slightly unwell for a few hours. It is a good idea to arrange to have the day off work, in case you need to go home and rest. Also, many women find it helpful to bring a friend or relative to support them and drive them home.

If your treatment was done under local anaesthetic you may have some period-type pains for the rest of the day, when the anaesthetic wears off. After these treatments you should expect to have some bleeding or discharge for a few days. This usually settles in two weeks but may last for up to 4–6 weeks. The bleeding should not be heavier than a light period and should get steadily lighter.

You should contact your GP or the clinic where you had your treatment if:

the bleeding starts to get heavier
the discharge starts to smell (which can mean that you have an infection)
or you have any other concerns.

Your doctor or nurse will probably advise you not to have sex for at least 3–4 weeks after your treatment to allow the cervix to heal properly. Treatments for CIN will not have any effect on your ability to enjoy sex once the cervix has healed. You may be advised not to use tampons for a few weeks. You should feel completely back to normal in about six weeks at the very most.

Research has shown that the treatments for CIN are very successful and do not usually need to be repeated. Women who have had successful treatment for an abnormal smear or LBC test are very unlikely to have a recurrence of the problem.

Follow-up after treatment

After any treatment for CIN you will need to be monitored for a time to check that the treatment has been successful.

If you had CIN 2 or 3, or cervical glandular intraepithelial neoplasia, you will have cervical screening tests 6 months and 12 months after treatment. You will then have a cervical screening test every year for 9 years.

If you had treatment for CIN 1, screening is done 6 months, 12 months and 24 months after treatment. If all these tests show that the CIN has gone, you will go back to the normal screening schedule – every 3–5 years, depending on your age.

Even if you have had a hysterectomy you will still need to have regular check-ups as above, with smears taken from the top of the vagina (known as a vaginal vault smear). Your GP or gynaecologist can organise vault smears for you – they are not done as part of the screening programme.

In 5–10% of women, the abnormal cells come back. If this happens, you will be invited for another colposcopy and further treatment if necessary. Usually you can have more laser treatment or a loop excision, or you may need a cone biopsy.

If the abnormal cells come back more than once, you may be advised to have a hysterectomy, to prevent you from developing cancer of the cervix. It is also sometimes possible to remove just the neck of the womb in an operation known as trachelectomy. Trachelectomy is an experimental procedure carried out for young women who want to continue to have the possibility of becoming pregnant. You would need to discuss all your options with your doctor.

Pregnancy and abnormal screening test results

Treatment when you are pregnant

If you are pregnant when you are invited for your routine cervical screening test, tell your GP or clinic so that the test can be postponed until after the baby is born.

If you become pregnant and have not had a cervical screening test in the last three years, you will probably be asked to have one at your first antenatal appointment. If the test result is abnormal, you will then be asked to have a colposcopy. It is safe to have colposcopy during pregnancy and does not cause any harm to the baby. Even if you do need treatment, it is usually safe to wait until after the baby is born.

Treatment for cervical changes and future pregnancy

Apart from a hysterectomy, it is very unlikely that any treatment will affect your chances of becoming pregnant or of carrying a baby for the full nine months of pregnancy. If you have had a cone biopsy, this can occasionally affect future pregnancies.

Your feelings and abnormal cervical screening test results

Fear

When a woman is told that she has an abnormal screening test result the first reaction is often one of fear. Many women may immediately think that they have cancer, so it is important to remember that the vast majority of women who have an abnormal result have early changes in the cells and do not have cancer.

Shame

There has been a lot of publicity about CIN and its link with sexual activity and HPV. This has sometimes led to women feeling guilty or ashamed if they have been told they have CIN. However, you should not feel that you are to blame in any way. Most women have HPV at some time in their life without even knowing it. Many women’s immune systems will get rid of the virus naturally.

Embarrassment

Understandably, many women may find the treatments for CIN embarrassing and possibly frightening. Don’t be afraid to ask the doctor or nurses as many questions as you like, as this may help to put your mind at rest. The Cancerbackup nurses will also be pleased to answer any of your questions.

References for the cervical screening section

The information in this section is based on the Cancerbackup booklet, Understanding cervical screening.

The booklet has been produced in accordance with the following national guidelines:

Guidance on the use of Liquid-based Cytology for Cervical Screening. National Institute for Health and Clinical Excellence. October 2003.
Making a Difference: NHS Cervical Screening Review. NHS Cancer Screening programmes, 2004.
Colposcopy and Programme Management: Guidelines for the NHS Cervical Screening Programme. National Health Screening Programme, Apr 2004.
National Cancer Guidance Group. Improving Outcomes in Gynaecological Cancers. Three Documents: The Manual; The Research Evidence; and Guidance for General Practitioners and Primary Care Teams. London: NHS Executive, Department of Health, 1999.
The Oxford Textbook of Oncology. Editors: Robert Souhami, Ian Tannock, Peter Hohenberger, & Jean-Claude Horiot. Oxford University Press, 2005