Cervical cancer screening
Cervical screening uses a test called cytology which most people know as the ‘smear test’. Cytology involves taking a sample of cells from the cervix with a small brush. These cells are sent to a laboratory to be tested for abnormalities. If borderline or mild changes are found, the sample will also be tested for high-risk HPV strains. If extensive changes are found, these will be treated.
By detecting and treating abnormal cells, screening can help prevent cervical cancer from developing. As well as preventing cervical cancer, screening can also detect cervical cancers at an early stage when treatment is most likely to be successful. Scientists are researching other ways to make the cervical screening programme even more effective, including the possibility of using HPV testing as the primary method of screening.
Who is invited for cervical screening?
In England and Northern Ireland women from age 25 to 64 are invited for cervical screening. Women aged 25 to 49 are invited every three years. After that women are invited every five years.
In Scotland and Wales cervical screening starts at 20.
How many lives does cervical screening save?
Scientists estimate that cervical screening saves around 5000 lives each year in the UK.
Cervical screening can prevent at least:
• 75% of cervical cancers in women in their 50s and 60s,
• 60% of cervical cancers in women in their 40s,
• 45% of cervical cancers in women in their 30s.
Since the introduction of cervical screening in the 1980s, rates of cervical cancer have almost halved.
What are the downsides of cervical screening?
Cervical screening is very effective but, like any screening test, it isn’t perfect. In cervical screening, very few tests will find abnormal changes that aren’t really there. But one in five tests will miss something.
Sometimes it is difficult to tell whether changes in the cervix will return to normal or progress to cancer. This means that some women will be treated unnecessarily, for changes that would not have caused any harm if they had been left alone.
It is hard to say exactly how often women may be ‘overdiagnosed’ or ‘overtreated’ in this way. But the benefits of preventing cervical cancers are so great that they considerably outweigh the harms of some unnecessary treatment in women from their early to mid-twenties to mid-sixties.
Why aren’t younger women screened?
In young women changes in the cervix are very common but they usually return to normal and don’t cause any harm. Screening these young women would be much more likely to lead to unnecessary treatment of these temporary abnormalities. Treatment for cervical changes can lead to complications in later pregnancies.
Do girls who have had the cervical cancer vaccine still need to go for screening?
Yes. Since 2008, girls aged 12 and 13 have been offered a vaccination against a virus that causes cervical cancer, called human papillomavirus (HPV). More recently, a catch-up programme has been introduced for girls aged 13 to 18 as well. This vaccine can prevent over 70% of cervical cancers.
There are very many strains of HPV linked to cervical cancer. Although the vaccine protects against the two strains that cause most cases of cervical cancer, it does not protect against all of them. This means that screening will still benefit girls who have been vaccinated.
What about the HPV test for cervical screening?
The current cervical screening programme is very effective. But new tests may prove to be even better. One new test looks for evidence of HPV rather than abnormalities in cervical cells. Otherwise, it involves almost the same process as the current ‘smear test’. More research is needed before policy makers can decide whether HPV testing should replace the smear test in the future.
Our current research
You can find out all about the research we are doing on cervical screening by going to our research highlights pages.
Find out more
As well as attending screening, it’s still important to keep an eye out for any unusual changes in your body. If you notice anything unusual, make an appointment to see your doctor and get it checked out.
Smoking can increase the risk of cervical cancer. This is because cancer-causing chemicals in cigarette smoke can enter the blood and travel around the body, damaging the cells of the cervix. To find out more, and get advice on giving up, go to our healthy living section.
Our CancerStats section has detailed statistical information on cervical screening.
Question about cancer? Contact our information nurse team