What part should HPV testing play in cervical screening?
Cervical cancer is the second most common cancer in women under 35 years old: about 2,800 women are diagnosed each year in the UK, leading to about 1,000 deaths.
The NHS Cervical Screening programme screens almost four million women in England each year, at a cost of around £157 million a year. It is estimated to prevent around 70% of cancers in screened women by detecting ‘precancers’ which are easily treated. The screening programme currently adopts liquid based cytology (LBC) as the primary screen to detect precursor lesions.
Testing for human papilloma virus (HPV) could add sensitivity to the detection of lesions, either alongside cytology, or as a first test, with cytology reserved for women who are HPV positive. But there was a lack of evidence as to the most clinically and cost effective way of combining these tests.
What we did
The NIHR funded researchers to test whether carrying out LBC alongside cytology was more effective than carrying out cytology alone.
Women undergoing routine cervical screening were recruited in general practices and family planning clinics. HPV tests were performed on cytology samples obtained at screening. Women either had the test result revealed, and acted upon if persistently positive in cytology-negative cases, or concealed from all parties.
What we found
Primary screening using LBC does not benefit from being combined with HPV testing. But the research suggested that using HPV testing as an initial test triaged by cytology would be cheaper than cytology testing alone.
In a second study, HPV as an initial screen was significantly more protective over a 6 year period than the current practice of cytology. Moreover, the use of primary HPV screening could allow a safe lengthening of the screening interval. A RAND assessment of over 200,000 people concluded that such a change offered a potential net benefit to the NHS of nearly £3 million a year.
The project has been closely followed by the UK National Screening Programme in England. In November 2015 and after reviewing all the evidence including the data from these trials, the UK National Screening Committee, recommended that the cervical cancer screening programme should adopt HPV as the primary screen test because it is a more accurate screening test.
Reconfiguration of laboratory services and IT infrastructure to implement these changes to the screening programme will take several years, so a robust evidence base to such major change is paramount.