HPV Testing Offers Women Protection For Twice As Long As Smear Testing

Nearly 3,000 women aged 35+ were recruited into the study between April 1994 and September 1997. They were asked to participate in a study in which HPV testing would be performed in addition to cytology (smear test) whilst attending their GP practice (40 practices were involved in the trial) for a routine cervical smear. Women who had previously been treated for cervical intra-epithelial neoplasia (CIN) -- changes to cells in the cervix that can develop into cancer -- or had experienced any cervical abnormality within the previous 3 years, were excluded from the study.

All women tested were followed up passively using data from the national computerised system that records all smears and their results -- the Open-Exeter system. Women with a smear history indicating the need for colposcopy -- a more thorough examination of the cervix -- were investigated further to determine whether the colposcopy and biopsy were performed, and what the resultant outcome was. Passive follow-up was complete for all women by early 2005.

Results showed that the risk of developing cervical abnormalities at 1, 5, and 9 years after a normal smear test was 0.33 per cent, 0.83 per cent, and 2.20 per cent respectively, with those odds significantly reduced after a negative HPV test - 0.19 per cent, 0.42 per cent, and 1.88 per cent.

Professor Jack Cuzick said: "Not only does the research confirm that HPV testing detects more disease at each smear, it shows that this approach offers women excellent protection from cervical abnormalities for at least 6 years after a negative test, compared to protection from a normal smear test which begins to wane after about 3 years. This suggests that the screening interval can be safely extended to at least 6 years with HPV testing. These data provide more support for replacing screening based on abnormal cells, with a more sensitive test based on screening for the human papillomavirus."