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About cervical screening

Cervical screening aims to prevent cervical cancer from developing. Find out more about the screening programme and how you have the test.

What screening is

Screening means testing people for early stages of an illness before they have any symptoms. For screening to be useful the tests:

  • must be reliable at picking up the illness
  • must be simple and quick
  • overall must do more good than harm to people taking part

What cervical screening is

Cervical screening is a way of preventing cancer by finding and treating abnormal cell changes in the neck of the womb (cervix). These changes could lead to cancer if left untreated. 

The screening uses a test called cytology, which many people may know as the smear test. A nurse or doctor takes a sample of cells from the cervix with a small brush. They send the sample to a laboratory to check for abnormalities.

In some cases, the samples are also tested for the human papilloma virus (HPV). This virus increases the risk of cervical cancer.

Who has cervical screening

The NHS cervical screening programme invites women from ages 25 to 64 for cervical screening. Women aged 25 to 49 are invited every 3 years. After that, women are invited every 5 years until the age of 64.

You need to be registered with a GP to get your screening invitations.

Why younger women don't have screening

We know from research that cervical cancer is very rare in women younger than 25. But changes in the cervix are quite common in younger women. So screening them leads to unnecessary treatment and worry.

Scientists have worked out that screening younger women leads to more harms than benefits.

The cervical screening test

The screening test involves taking a sample of cells from the surface of the cervix. The test is called liquid based cytology (LBC).

To have the test you take off your underwear and lie on your back on a couch. You need to lie with your knees drawn up and spread apart. If this position is difficult for you, you can ask your doctor or nurse to take the cell sample when you are lying on your side with your knees drawn up.

To take the sample of cells, your doctor or nurse gently slides an instrument called a speculum into your vagina so that they can see the cervix clearly. Having the speculum put in may be a little uncomfortable, but it shouldn't hurt. It can be more uncomfortable if you are very tense. Try to relax. Taking a few deep breaths can help. 

Your doctor or nurse gently scrapes the surface of your cervix with a small soft brush. This collects a sample of cells from the outer layer of the cervix. They put the sample into a pot of liquid and send it to the laboratory. Then they take out the speculum and the test is over. You can get down from the couch.

In the laboratory, a pathologist looks at the sample under a microscope. They examine the cells and report any abnormal ones. They may also test to see if HPV is in the sample. 

HPV testing

In the next couple of years, primary HPV testing will be rolled out across England and Wales. This means that they will test the sample of cells for HPV first. If HPV is found, they will then test for cell changes.

After the cervical screening test

You usually get the results within 2 to 6 weeks. Ask your doctor or nurse when you have the test how long to expect to wait for the results.

Screening results

There are several different results that you might have after a cervical screening test. Most women have a normal result.

Benefits of cervical screening

Research shows that cervical screening prevents at least 2,000 cervical cancer deaths each year in the UK.

Women screened between the ages of 35 to 64 are thought to have a 60 to 80% lower risk of being diagnosed with cervical cancer in the 5 years following the test compared to women who haven't been screened. The benefit of screening increases with age.

Since cervical screening started in the 1980s in Great Britain, rates of cervical cancer have almost halved.

Possible harms of cervical screening

Cervical screening works very well but, like any screening test, it isn’t perfect. In a few cases, tests will seem to find abnormal changes that aren’t really there. This is called a false positive result. It leads to unnecessary worry for the woman and also the need for more tests. 

There is also a risk that cell changes may be missed. This is called a false negative result. So it is important to go for screening every time you are invited.

Sometimes it is difficult to tell whether changes in the cervix will go back to normal or will develop into cancer after some years. So, some women will have treatment for changes to cervical cells that would not have caused any harm if they had been left alone. This is called overdiagnosis or overtreatment. 

For a few women, the treatments may cause problems such as bleeding afterwards or a small increase in future pregnancies of having the baby early.

It is hard to know exactly how often women are overdiagnosed or overtreated in this way. But in women from their early 20s to mid 60s, the benefits of preventing cervical cancers are very great.

HPV vaccination

Since 2008, girls aged 12 and 13 have been offered a vaccination against the human papillomavirus (HPV). The vaccine can prevent over 70% of cervical cancers.

It is important for girls to have the vaccination when it is offered at school. But there are many types of HPV linked to cervical cancer. Although the vaccine protects against the 2 types that cause most cases of cervical cancer, it doesn't protect against all of them. This means that screening is still important for girls who have been vaccinated.

If you have symptoms

As well as attending for screening when you are invited, you still need to look out for any unusual changes to your body. Check for:

  • abnormal bleeding (such as bleeding between periods)
  • vaginal discharge that smells unpleasant
  • pain during sex

See your doctor if you notice anything unusual. There are many conditions that can cause these symptoms. Most of them are much more common than cervical cancer. But it is important to get your symptoms checked out.

Last reviewed: 
05 Jun 2017
  • HPV testing as a triage for borderline or mild dyskaryosis on cervical cytology: results from the Sentinel Sites study
    RS Kelly and others
    British Journal of Cancer, 2011. Volume 105, Issue 7

  • Impact of cervical screening on cervical cancer mortality: estimation using stage-specific results from a nested case–control study
    R Landy and others
    British Journal of Cancer, 2016. Volume 115, Issue 9

  • Effectiveness of cervical screening with age: population based case-control study of prospectively recorded data
    P Sasieni and others
    BMJ, 2009. Volume 339

  • Cervical Screening Programme England, 2015-16
    Health and Social Care Information Centre (HSCIC)

  • Cervical screening Wales
    NHS Wales, July 2016

  • Cervical screening programme Scotland
    National Services Division, NHS Scotland, July 2016

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