Testing for the human papillomavirus (HPV) as part of cervical screening reduces the number of women unnecessarily going on for further tests by over a third, new research shows today.
The results are from the first evaluation, led by The Institute of Cancer Research, of the ‘Sentinel sites’ project to make HPV tests available to women as part of cervical screening.
The study*, published in the British Journal of Cancer**, looked at over 10,000 women aged 25-64 who were part of the NHS Cervical Screening Programme and whose first smear test had shown mild or borderline abnormalities in the cervix.
These cervical screening samples were then tested for HPV – the results showed that around 35 per cent (3581 women) were HPV negative and were able to return to routine screening.
Women with a positive HPV test result were then referred for a colposcopy (internal examination) without having to go through further smear tests.***
While most women infected with HPV do not develop cervical cancer, the virus is a major cause of the disease.
Study author Dr Sue Moss from The Institute of Cancer Research said: “Our study shows that adding HPV testing significantly reduces the number of women sent for more invasive tests, when in fact they do not have any serious cervical changes.”
The study analysed the first phase roll-out of HPV testing for borderline or mildly abnormal cytology tests, which began in 2007 at six laboratories in England.
This research gives an insight into the likely effectiveness of the NHS Cervical Screening Programme by including HPV tests in the process at a national level.
This has started being rolled out as part of the existing NHS Cervical Screening Programme since April this year.
One thing that the research highlighted was that the proportion of women who will be referred for colposcopy will vary between laboratories because of differences in how mild or borderline changes and HPV test results are interpreted.
Sara Hiom, director of health information at Cancer Research UK, said: “This is a welcome refinement to the highly effective cervical screening programme. This change has already saved thousands of women an anxious wait for extra tests and results, and should help lead to a more efficient screening programme.”
Professor Julietta Patnick CBE, director of the NHS Cancer Screening Programmes, said: “The NHS Cancer Screening Programmes is very pleased indeed with the results from the Sentinel Site project. The use of HPV testing that this paper reports is currently being incorporated into the screening programme nationwide and will be fully rolled out within the next year.
“By incorporating HPV testing into our current screening programme in this way, we will be able to significantly reduce the number of repeat cytology tests required and to target our colposcopy services more effectively. This is an important development in our programme enabling us to screen women more effectively and efficiently, reducing unnecessary procedures and minimising any associated anxiety.”
**Moss SM et al., HPV Testing as a triage for borderline or mild dyskaryosis on cervical cytology: results from the sentinel sites studies, British Journal of Cancer (2011)
*funded by NHS Cancer Screening Programmes
Up to 8 out of 10 people in the UK will be infected with the HPV virus at some point in their lives. HPV infections are usually on the fingers, hands, mouth and genitals.
For most people, the infection will get better on its own and they will never know they had it. But in some people the infection will stay around for a long time and become persistent. Persistent infections are more likely to lead to cervical changes and cervical cancer.
Laboratories from the following areas were involved in the 2007 ‘Sentinel sites’ roll-out: Bristol, Norfolk & Norwich, Liverpool, Manchester, Sheffield and Northwick Park – representing approximately 10 per cent of the English cervical screening programme.
***NHS Cervical Screening Programme
Cervical screening 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).
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.
It is estimated that 4,500 lives are saved every year in England through cervical screening. The NHS Cervical Screening Programme routinely invites women aged 25 to 49 for a cervical screening test every three years, and those aged 50 – 64 every five years.
At present, the NHS Cervical Screening Programme tests women using a technique called liquid-based cytology (smear tests). A sample of cells is collected from the cervix and analysed for abnormalities which, if left untreated, could lead to cancer in a woman’s cervix (the neck of the womb). Women who are found to have severe abnormalities are referred for a more detailed examination of the cervix known as colposcopy followed by treatment if necessary.
Under the current system women with borderline changes are offered repeated tests with liquid-based cytology. Those with persistent borderline results are offered colposcopy.
HPV triage is a process by which samples from women containing cells with low-grade abnormalities (borderline or mild dyskaryosis) are tested for high-risk HPV strains and, if positive, the women are referred to colposcopy. These low grade cervical abnormalities only have a 15 per cent to 20 per cent chance of needing treatment and may clear up on their own but it does mean that women, whose samples are high-risk HPV-negative can be returned to routine recall as they are at negligible risk of developing cervical cancer in their current screening round and have a comparable risk to a woman with an otherwise normal cytology screening result. Consequently this means that women with low grade abnormalities can be more effectively triaged into subgroups that do and do not require colposcopy assessment.
Alongside HPV triage, the sentinel site project also reviewed how to incorporate HPV testing after cervical intra-epithelial neoplasia (CIN) treatment, a process called ‘test of cure’. Generally, after a woman has been treated for abnormal cells, she is recalled for screening every year for up to 10 years. However, if a woman tests negative for both HPV and abnormalities then she can be included within the regular screening programme, rather than tested annually. This is likely to save even more tests.